This is the SS with ADHD, right? Also taking behavior therapy? Has DH talked to the person/s doing the therapy sessions and asked about what Dad can try at home? You mentioned once (sorry if I'm remembering incorrectly) that SS takes ADHD meds while at BM's, but not at your house and it's also BM who takes the kids to therapy.

I guess what I'm asking is, do the people doing therapy with the kids actually know how the child/children behave and interact in your home and during Dad's time or is the sessions based purely on what BM tells them and during times the child is taking his meds (BM's time).

"I was so pissed off because this kid doesn't think of anyone but himself and what he wants at the time." Sorry, pretty much all kids are like this..lol. Not a lot of empathy. they are soul suckers

A little advice on the two issues.

1. Food ordered and not eaten. Ok.. STOP giving the kid the choice to order his own meal. Just stop. Dad needs to pick something on the menu for the kid and order it for him. Child's menus are offered at virtually every restaurant. Get the child's menu and perhaps if he wants give the kid the choice of THAT menu only. That's it. Restaurant meals are too big for most adults to eat everything. In fact, maybe dad could just share his plate with his son.. maybe add a salad or bowl of soup?

2. Behavior... sorry, you are going to have to break some eggs to make some omelets. The kid isn't going to learn to control himself in public and behave if he doesn't have the opportunity to do it. So a couple tips.
First, pick places that are kid friendly and known to bring the food out fairly quickly. Long drawn out meals are tailor made for kids to become bored. It's not fair to do that to him while he isn't yet able to control himself better. He will always fail if you do that. You can go to other places as he learns.

Second, before you go inside, your husband goes over the rules with him:

"We are going in here to have dinner, I expect you to be on your best behavior and that means that you will use your inside voice, stay seated and not bother other diners. You will eat using your best manners which means no chewing with your mouth open, do not interrupt adults and do not play with your food. If you can't manage to behave then I will take you outside and you will miss dinner while everyone else finishes their meal". Then, if kid starts to get a bit antsy or whatever, dad asks him "do you want to outside and miss the meal?"

Now, none of this is delivered with yelling and histrionics... dad matter of factly tells him "ok bucko, you were warned. I told you that if you didn't sit in your seat that we would have to leave. Ok Tankh.. you enjoy the rest of your meal, we will see you outside"

Then outside it's not a fun time right... you sit the kid in the car and tell them you are disappointed in them.. then silence... let them sit and ponder the fact that everyone else is inside and they aren't.

I have eaten in a Wendy's in front of my SS without ordering him anything. I was taking care of SS and SD because DH had to work. I had to run to the store and told them if they behaved I would get them fast food. Like always, SD was well behaved and SS was a brat. SS had to watch me and SD eat burgers and fries. He got a PB&J when we got home. I didn't care if DH or BM got upset.

Also, for close to two years, I refused to go anywhere in public with SS. I still will only go to limited places with him. DH used to complain about how we don't have fun together anymore. I told him to teach his kid to behave and I'll think about being in public with him.

Your DH needs to do the same thing. Limited the fun places until YSS learns to behave. When you do take him places, leave immediately if he starts acting up. I have made SS bring a book and sit on the sidelines while everyone else had fun. Actions have consequences.

It is pretty typical for parents to not give their kids ADHD meds on the weekends. I have never done it but my sons doctor says about half of parents do. I think it is harmful because all they do is get in trouble when not on their meds.

My sons ADHD meds make him not have an appetite during the day. I make him eat a big breakfast, he takes his meds, he usually does not eat lunch and then eats a big dinner. Maybe he just isn't hungry?

I would order for him or make him order off the kids menu.

Can you tell BM that she needs to send his meds/let you know if he is on meds/what his diagnosis is or you will be taking him to a ADHD specialist this summer when you have him?

I have a son who is on the spectrum. Super mild, you would never know until you got to know him. Some tactile issues, a bit of obsessive behavior, inability to cope with situations, easily overwhelmed. And the fluorescent lighting in many places makes him nuts!

So, I only get after him if it is necessary. I try to accept that he is weird in some ways and he can work on it but Rome being built in a day and all that. But the things that he can control? He knows if he acts like a shot his punishment will be swift. I don't wait, I immediately correct. And my kids have a healthy fear of me losing my shit. It doesn't happen often but when it does... run!