You have a bad foot fungus. His toes look wet because it's moisture and pus from him rubbing and scratching between his toes. Possibly did it with his socks on. That split is a result of that too.
I had a mild case of that in HS from running track and wearing tight ass kicks.
You gonna have to go to the foot doctor and take that shot bruh. They're gonna cut all that shyt out and remove some toenails too. Then put a cast on it. They'll give you some meds too.
Just go before your feet fall off nikka