Can I ask, how far away does your son go to school from you and when he is on break where does he stay?
It sounds like your son is very mature.
Can he have friends over and such...do you have to handle home phone calls for him, does he have his own bathroom and section of the fridge/cupboard for his food? What about TV, does he have his own? Internet access, does he use up all the bandwidth when he's home? Facebook, are you guys 'friends' and do you constantly look at his page?
My son's college is 4 hours away.
On break, right now he's in boot camp.
Last year he was here during the summer but he worked landscaping so left early got back and slept, and then generally went hiking or cycling or out with friends.
Other times he stays with friends, which is where he would rather be anyway. Some of his friends have large houses or like summer houses or their families do and so an extra guest is nice and they are set up for it. He has a girlfriend so spends a lot of his time with her and her family but they also visit here and go to her family's vacation place in a neighboring state.
By cutting the apron strings I mean you don't monitor even things like what classes he is taking, grades, not even knowing where he is on a day to day basis...
The way you know you've done this is you answer the phone and it's been a while and you say, who IS this? And you find out, that's your kid's voice. The one you have not been thinking about every single day. Then the landscape has changed. If they have an accident or whatever, you think, you will go and help if they ask for help, but you realize that it is no longer your job to help them adjust or whatever unless they specifically ask.
My son has a friend who had to distance himself from his nuclear family because the nuclear family had some issues. Their 'help' his first year of college was not very 'helpful'. Another friend the mom does hover but the friend has bipolar and so it is necessary. There have been car accidents, courts, not taking meds, etc.
I know a lot of parents really want to help their kids through college. So I guess it has to be decided do you want to parent through college? If neither of you was parenting when you were your son's age, it's not something that's stored in your innate memory...so maybe some support group/counseling would be helpful. You are definitely in uncharted territory.
I hope you do see your 13 year old and spend time with him/her.
Your H does seem to have some issues. He should be concerned about why he is blowing up on his child like that. It's also not good for the other kids to see that. As they mature, they need to feel secure.
I don't think the transition to adulthood is ever easy. Cutting the apron strings for me ended up being just that - a definitive cutting. Kind of like when they cut the umbilical cord and then sure enough, baby really does find a new way to eat.
I do think your H wants you all to himself but probably he thinks it would be selfish to say so. Is there any way you can set up an in-law apartment in your house and move into it? Maybe a garage apartment or something?