Can the ‘Devour Intellect’ ability be used through walls?

Question

I’m looking for clarification on how the abilities of the intellect devourer interact, especially with regards to obstacles. Firstly, it has blindsight of 60ft:

A creature with blindsight can perceive its surroundings without relying on sight, within a specific radius. Creatures without eyes, such as oozes, and creatures with echolocation or heightened senses, such as bats and true dragons, have this sense.

Without other knowledge of the intellect devourer's anatomy, it would seem this ability is psychic. This is augmented by a second trait:

Detect Sentience. The intellect devourer can sense the presence and location of any creature within 300 feet of it that has an Intelligence of 3 or higher, regardless of interposing barriers, unless the creature is protected by a mind blank spell. (MM 191)

The ‘Devour Intellect’ ability states:

The intellect devourer targets one creature it can see within 10 feet of it that has a brain.

Is it safe to assume that the ‘it can see’ line specifically requires line of sight, or would the two initially quoted traits work in conjunction within ten feet to allow the ‘Devour Intellect’ ability to work through barriers?

Answer 1

Not as you specify

Detect Sentience. The intellect devourer can sense the presence and location of any creature within 300 feet of it that has an Intelligence of 3 or higher, regardless of interposing barriers, unless the creature is protected by a mind blank spell. (MM 191)

Detect sentience does not allow the intellect devourer to see the target, it merely senses their presence. It knows where they are, but it can't actually see it.

As you already stated yourself, the devourer needs to be able to see the target to use its ability:

The intellect devourer targets one creature it can see within 10 feet of it that has a brain.

However, RAW, the devourer would be able to target somebody that they can see but can't physically reach behind a see-through barrier, such as behind a glass wall.

If it wins the contest, the intellect devourer magically consumes the target’s brain, teleports into the target’s skull, and takes control of the target’s body.

So as the rules are written, a transparent see-through barrier will not stop a devourer, but one they can't see through will.

On blindsight: It was brought up in comments that the devourer technically can't ever see anything because it has blindsight. There is already a question on blindsight and seeing through walls that comes to the conclusion that blindsight does not work through walls, but it won't answer if "seeing somebody without seeing them counts as seeing them". This answer assumes that anything you can perceive with blindsight or darksight counts for seeing a creature, but abilities that 'sense' locations do not.