There is another thing in here to add to the feedback about why won’t be moving up. If he is the only one he knows the stack, and he isn’t personable enough to work with for a hand off (for most of the team), he had stuck himself in that role. Some people think if only they can do a certain job it means security, but what it really means is they can never be promoted.

If he wants to move up he needs to show that is can successfully work with people and have everything off, so he isn’t a single point of failure.

Being a lead is also more than hard skills, it’s soft skills and being able to work with people, which sounds like a weakness.

If he is serious about wanting to move up, there are lots of things he needs to address here, not just his attitude towards you.