OP, I really think you see impossibilities where other people might start thinking about possibilities. If he has to eat the same food as the rest of you, why can't he just heat it up when he gets in?
In our family, I often work later, dd (20) sometimes works very late, ds (16) sometimes likes to go to the gym in the evenings. Supper is served at 7.30-ish to anyone who happens to be in at the time; anybody who comes later eats the leftovers. This is not difficult. We still have plenty of family meals.
I understand your anxieties and the pressure you are under, but unfortunately that won't let your ds off the hook when it comes to needing to judge situations and friends for himself.
I have given my own teens that little bit more independence, I have let them understand that I am always happy to discuss situations and that they never need to think of sparing my feelings because there is nothing that mum is not tough enough to deal with (all right, so I may have to fake this bit 
), but that I believe in their judgement and ability to sort things out.
The results has been very encouraging. Tricky situations have arisen:
a friend getting too drunk at a party
a friend being injured at a party after getting too drunk
a suicide attempt
a friend reacting badly to medication when alone with one dc
And each time I have been reassured to hear that dc have acted calmly and responsibly and done the right thing. And yes, reassured is the word I use deliberately. Not anxious because the situation arose, but reassured because they could handle it.
While Userone's link is good, this is about friends that you as a parent have reason to believe are bad friends. Making the assumption that any friend you don't know is bad is likely to leave him unable to differentiate between good and bad and unwilling to exercise his judgement.