I've actually played a game where another player wanted to do the same thing.
Normally, the character operated under the blinded condition; however, depending on the character, they may instead opperate under the [blind] keyword. I know you said he has done research himself, but it is important for me to show this to you, because a lot of the things require you to overlook the rules. I'll go over 3 augmentations I'm familiar with, and then go over a few options you can take to apply to the character.
In the adventurer's vault there is an item called "Grimlock Helm". It has a minor action daily which gives blindsight 5 until you deactivate it. For a normal character, having an item like this would be a trade off, because it causes a "visor... to cover your eyes," but if you're permanently blind, you can use it all the time. It is a level 17 item, so its up to you as far as if/when he gets it.
The DM said that as long as his background incorporated it, he could have it to start and his character would be blind. It really didn't make him too OP.
The DM allowed him to take the Blindfighting Sentinel (Essentials) feat. In the description, it says while you are blinded you don't grand combat advantage and you don't take a minus to perception, AND you get a +2 to Perception.
There is also a feat called Blindfighting Warrior which allows you to ignore concealment while blinded, also in Essentials.
Now, if you're blind, you can't be blinded, but the DM overruled that to make the character more balanced. The only reason he did this was because we fought a lot of ghosts that game as well as ranged troops, so the charater was still a bit underpowered.
Now, those are a few augmentations, but here are basic setups for the blind character based around 2 archetypes: Newly Blind and Born Blind
Newly Blind: Touch-based, Grimlock Helm, Sound-based, and Touch/Sound
Newly Blind Characters would be characters that lost their sight later in life. Based on your campaign, make them the Touch-based, Grimlock Helm, Touch/Sound or Sound-based Newly Blind Character. FYI, Touch- and Sound-based do include house-ruled "spells." Its not really a house rule, since its technically something a character could do with their minor action, but it isn't described in any book. Skip to Grimlock Helm for no houseruling.
Permanently apply blindness, thus allowing for Blindfighting Sentinel and Warrior. Taking both of these feats effectively will cancel out all of the minuses but you can't do much.
Give the character an at-will minor action utility called "Feel," which rolls Perception vs. Reflex. It would be a close burst one, targeting either one, or all creatures in burst (your choice), and if successful, allows you to "see" the character until the start of your next turn.
An alternate way to do this is to do a Perception roll against a DC check of whatever you decide to give tremorsense 1 until the start of your next turn.
(optional) When a character "sees" an enemy, their token will remain in that square (for his turn) that he last saw them in. He can still target these characters, but if they aren't really there, the attack automatically fails.
Sound-based is the same as Touch-based, except instead of "Feel," the character gets "Hear," which would be a close burst (whatever range you decide) to get a general idea (3X3 square) of the enemy's location. The character can target any of these squares, but if the enemy isn't there, it fails and if they are, the character takes a minus to the roll. This offers more range, but less accuracy than Touch-based.
Just combine Sound and Touch and there you go. The character gets both of the abilities.
The character has the Grimlock Helm
Permanently apply blindness, but only to squares outside of the 5 squares of blindsight. Inside the squares, the character operates under blindsight.
Blindsight, at least in terms of Grimlocks, opperates through sound and smell, according to the Monster Manual.
As such, the DM can interpret this to mean that if a character wearing the Grimlock Helm has one of these senses disabled, they cannot use the blindsight, but I do not agree for the following reason:
The Grimlock Helm is a magical item while Grimlocks are Beserkers and Ambushers (not magically inclined). As such, it should be infered that this is merely called the Grimlock Helm due to its indirect similarity to Grimlocks, not to its direct relation.
Characters who have been born blind (or have been blind for a really really long time) are naturally going to be better at navigating the world, so, instead of giving the blinded condition, give them the [Blind] keyword, thus taking away the minuses associated with this. It also takes away the ability to get blindfighting feats. A [blind] character and a blinded character with those feats essentially operate the same, except the [blind] character has 2 more slots for feats.
Even still, you're left with a character who can't do much, so i've set up the same subsets as before. Also, I did some research and read in real life that some people who are born blind actually rely heavily on SMELL to navigate, so i made a bit of a more lighthearded subset for Olfactory-based Born Blind Characters. The combination for these 3 senses works as it did above for Touch/Sound- Based.
The same as above, but, since the character has grown up with this sense of navigation, you can choose to make "Feel" a free action, with the same effects as usual.
This works as sound above, but you can choose to make "Hear" a free action, with the same effects as usual.
This would work as the others, except instead of "Hear" or "Feel" the character would get "Smell" as a close burst (whatever you choose). It is a Perception DC roll and if successful, will give a general range like "Hear" except it will be more accurate the stronger the character smells
Determining range for Smell can either be based off of Charisma (there's not exactly a Smelly stat, but this comes the closest) where the area could be equal to a (Cha mod X Cha mod) square, or it can be based off of the GM's discretion.
your good old rule-friendly version works exactly like above.
OP, while I did include options for rule-friendly building, since you're already going off of what is expected by the rules (a blind character) I also included house-ruled options. I know the character wants the mechanics for it, so I included it because of the lack of mechanics inherently created for a blind character. That being said, if you would like for me to take the house-ruling out, just give me a comment and i will gladly edit it.
Based on the path you and your characters choose to take, your blind character could go down a variety of paths. Unfortunately, there is little information regarding how to work with blind characters, resulting in a big requirement of interpretation on your part. There are ways to make a blind character in a rule-friendly manner, but if you do wish for some greater personality and tactics for you character, a little bit of house-ruling can do the trick nicely.