I am currently running Lost Mines of Phandelver for a fluid group of about 10 people. We play once a week and on a given night 4-6 people will show up. We've been doing this for 4 months now. I have very limited experience as a DM so for all intents and purposes, I am new. At this point most of the players have a working understanding of how their classes work and what their various class and race specific quirks and abilities are.
Whenever someone forgets something relating to their class, I'll pass them the PHB or basic rules and let them look it up on their own. If there are questions regarding the rules, I look up the answer myself. I've never explicitly stated this but it's the precedent. It is very important that players are expected to be as self sufficient as possible because we have a large group and I'm stretched thin.
I have a problem player (PP) who wanted to be a sorcerer. I told him that he'd have to keep track of his spells and more stats than everyone else and that he'd probably have more fun playing a non-magic class but he insisted. I handed him the PHB to choose his spells and he chose all of them at random.
Below are the primary issues, most of which come up during combat, and what I've done to remedy them:
PP does not know what any of his spells do but tries to cast them anyway. Whenever he casts a spell I'll ask him what it does or if he has the requisite materials and he'll say he doesn't know. This turns into me pausing the flow of the game to look up the spell, explain it to him, and then continue. I have tried asking him to write his spells down but that results in the next problem.
PP takes horrible notes. He'll write out a couple words on a spell that he can't decipher later or straight up write the wrong spell down. He does the same with his ability scores and stats. We've had to reroll his health before because he was not tracking max health. He is so inconsistent and disorganized that we have to recalculate his stats for every relevant action he takes. This also annoys the other players because he is constantly losing items. I give him unlimited crossbow ammo as a courtesy and match his xp to the average of the other players.
I've asked PP repeatedly to print out all his spells from the wiki or something but he forgets every time. I would do this for him but then I'd have to do it for everyone (I have far too many players) and I don't want to set a precedent of being a nanny. Also I'm afraid that if I give him any more help he'll expect me to track everything for him. So, I keep holding up the game to look up spells and ask him to do something about this. He understands the problem but does not deal with it.
PP does not understand the larger meaning behind any of the numbers. All of the other players understand that difficult actions require higher rolls and they have a feel for when their health is low. PP doesn't get this and won't do anything (including self preservation) but fire his crossbow unless the other players ask him to. I encourage him to read the PHB. I've sent him links, I've put the book in front of him, he'll open to a page to humor me but won't actually read. I don't want to lend him my PHB to read on his own because he has a history of forgetting things at home.
I don't want to kick him out. He really shines during the RP segments (he even uses spells outside of combat very effectively) and he's a fun player but he is such an impediment during combat that I need help dealing with him. Other players will occasionally memorize spells for him or look things up while I'm doing other things but we're all new and the table gets easily frustrated.
What should I do?