Debi I bet you know he is probably testing you - if I scream loud enough I'll get what i want.
I truly sympathise. We have days like that from C (hence yesterday's tantrum). Normally it's because we have switched the TV off or want to brush her hair and she SCREAMS!! She also sobs and if we're out, you get the stares.
I used to get really wound up but then realised it was winding her and DP up too, so I tell myself it's just her age, she can't help it but I don't give in. I even cuddle her while she cries and then explain why I'm not giving her what she wants when she stops. i tell her I love her and I hate to see her upset but [repeat internally over and over] I am not giving in.
DP loses his temper more easily and it does make her worse when she sees it's affecting him.
With 2 boys, you have way more experience than me but FWIW, if this were me I would not make DS2 a seperate meal - he won't starve long term.
If C tantrums during a meal and really won't stop, we push her chair out a little bit so she can't grab anything and explain we'll talk when she's calmer and let her get on with it.
Yesterday, she barely ate any lunch and refused her snacks so by 5.15 she was in her chair screaming for food. It was damn hard but I explained that's why she should eat earlier. When her tea came, she wolfed it down.
Again, FWIW if she was refusing food regularly, I would give her our meal but do a small side plate or pot of healthy things I know she'll eat to go alongside her meal eg some cucumber, tomatoes and a couple of breadsticks. Then at least if she eats these, she has something but it's very much a side dish and not lots of snacks during the day.
Don't know if this is helpful (am on work on a slowww day) and sorry for writing loads!