Friend is letting others taken advantage of him financially

My friend works 2 jobs to support himself and has several friends who are on disability that he frequently pays for their meals dining out, other social events & giving them free transportation. The "friends" do have legit disabilities, I feel like he shouldn't make it his problem. It makes me sad to watch him do that when he's working his butt off at 2 jobs. He has been "friends" with them for many years so I know he won't change.

Sounds like he doesn't have any self respect.

I don't think their using him. It sounds like he is doing this willingly if it bothers him I think he would tell somebody, make them pay, or stop going places with them. But really I think it sounds like he enjoys their company and doesn't mind paying.