Ahhh....You are so kind for taking him in.
I think he really, really needs to see a Vet. If you can't afford that right now, I would suggest contact a Reputable Florida Rescue ~ Check this link out:
Home
Being in his condition and out on the streets, he probably has a lot of things that need medical attention and really should be addressed sooner than later. He probably needs a Vet dewormer and antibiotics to start
Please keep us posted - (I am crying just thinking about his 'hard' times out on the streets)
-Nicole
P.S. Welcome to YT