Not really sure what his dad has to do with him doing the thing that tons of guys in their late teens and 20s do which is try desperately to grow facial hair because they think it makes them look more mature and manly even when they clearly don't have the capacity to grow it
the only thing worse than no beard is a wispy, patchy scraggly mess and unfortunately that is where he has landed, basically every social media guy who is 'cute' rather than 'handsome' does this (and usually gets a bunch of tattoos as well) - he'll phase out of it eventually
Id also assume he's still spiraling from losing all of his muscle mass - for a while that is basically the only thing he cared about and did with his life he is still trying to do whatever he can to control his look, gyming isnt possible for him (maybe ever) based on the extent of his injuries and the residual effects so this is what he is doing