Yes, he'll complain but ultimately, even though he's family, he's not your responsibility. You've already done plenty for him; your brother is more than old enough to take care of himself at this point. If he didn't have a history of hitting you up for money or not holding down a job, I'd be more sympathetic, but that doesn't seem to be the case here.
That being said...yes, plenty of adults play video games, including myself. But we either play them in our spare time or we get good enough to somehow make a living doing so 😁.