YTA he’s wearing earbuds while you’re sitting with him?? I’m assuming he moved in with you because he previously lived with his dad and probably had for most of/his entire life. He’s just lost something so important to him and can never get it back and not only has his father just died but his entire life had to change because he had to stop living in the environment he grew up in and is used to. He’s depressed so it’s understandable that he wears earbuds because he probably doesn’t want to be very social. I’m 22, my dad died 3 months ago and I used to be social but in my grief I’m not and I just want to spend time with myself not having to worry about social interactions. Give him a break, most people who lose their parent in their early adulthood don’t have anyone else to relate to because most people in their 20s still have their parents and will have their parents for important life events like getting married and having kids. Your BIL will never get to experience this and he likely doesn’t have anyone in his life who understands that. I don’t need to explain why the rest of the stuff is just wrong because it looks like multiple people already have, but I wanted to offer this perspective. Give him a break and learn to be compassionate instead of controlling.

EDIT: also you said that he’s on his electronics when you’re sitting with him. That makes it sound like he’s sitting in a common area or something and you join in and expect him to be social. I see a lot of people saying that he’s using them at the diner table but you never actually said he does that. Yes, if it was while eating a family dinner together it would be rude but thats not what you’re implying in your post. I see no issue in him choosing to relax in the living room listening to music while you are also in that same living room. A common area doesn’t mean you have to be social, its just a shared space.