I think there are certain hills you must die on and the rest you have to suggest then let it go.
Easier said than done. Ie dinner is dinner, we know you like it but we aren't a restaurant you don't put in a request and we jump. Manners are expected of all children and adults (kids get really into picking up if needed and his dad aren't polite) so that's always a source of amusement.
Money's been a issue here of late. Bills, essentials come first and it's allocated at beginning of month and literally cordoned off. Whatever is left over is up to parent to spend on children as they see fit and I don't (anymore 😵💫🙄🙄) bail DH if he's blown all his money on a random game DSD needed that min and doesn't ever play and then grizzles he has no money rest of the month. I point out that he needs to manage his money more effectively like I do mine and maybe he won't have a problem next month but say the choice is his. We have a excel document for all bills costs which has been a life saver.
When kids tell me they are bored I ask what do they want me to do about it. And say I can charge them for entertainment but it will cost them and that usually brings a smile and light hearted response from kids. It's about quite boundaries and enforcing them. If they want cinema ect I say well we can plan it for next month on this date and put it in diary so kids know it's happening and can get excited, that gets added to the money spreadsheet and we go on. It's amazing how much these random days out cost and I'm not made of money.
My advice find the hills your going to die on. You not your DH (because his hills are dictated to by the whims of the kids).Plan accordingly. I didn't realise money was at the root of my frustration until I was that frog in the hot water. Check in with yourself.
If he's grizzling about the kids being rude suggest ways to tackle it (or if he's just venting nod, smile and detach in your head) and then say cheerfully but it's his domain, his parental choices and I respect your choices and whatever consequences those choices brings you will have my full backing. That usually enough for me to stop feeling guilty I haven't got a magic wand to fix all the problems. I would also make sure your not cross when you say that out loud or it will come across narky.
Sometimes Disney dads need to know it's their choices that lead to the kids behaving in a certain way and that's actually not there kids fault as he sets the tone.
Don't let him complain and put the responsibility on to you or the kids. Act as a team mate, and if your team mate is slowing down, don't keep trying to drag him with you. 100lbs of man is heavy to drag.
Wine helps too xx