To think this dad is being very rude and inconsiderate?

Message the Dad explaining it's just a family outing with bestie invited for DS Birthday. Say you're happy to meet up later in the day if he's taking his younger Son & will text him when you're there to arrange a time to meet. Have your time with the family & bestie then maybe an hour or so before you're leaving arrange to meet up for snacks & a drink for the kids. If he insists on coming with you all day you may have to suck it up for the sake of your Son spending his birthday with his friend.

I think YABU. There’s MANY reasons why Marks parents might want to be there (as many other pp’s have pointed out)
Plus with a little one who feels like they’re missing out… what’s wrong with that?! They ARE missing out. Who the hell are you to dictate they should miss out just because it’s your DS’s birthday. It’s a public venue… they can pay to enter the place if they want to. It’s not a personal attack on your DS. I think you need to get over yourself tbh

I think I would agree to them coming along in there own car.

I mentioned to a woman I knew that me and OH were taking our son to Blackpool and my OH friend and son were also coming.
She asked if her and son could tag along.

I said no problem and she asked if we had been before.
I told her we went twice a year as my son totally loved all the big rides and just had no fear.

When we get there her son refused to go near the big rides so she expected both my son and his friend to go on all the smaller rides with her son.
I felt sorry for the child but I had to put my foot down.
With cueing there just isn't time for my son to enjoy all the big rides and also go on the smaller ones...and that is the reason we are here.
She spat the dummy out

So maybe have the conversation if you think something like this may arise

I'd just say "lovely, sounds good. I don't think we will all fit in one car as there's 7 in total. So do you want to meet us there at ... The kids are gonna have lots of fun!"

I would just let it go. Like what’s the point? It’s really nice they want to spend the day with you and you are not paying for them so really what’s the issue? Go and have fun

'Yes its fine but we'll have to use 2 cars so meet up there at about ? Oclock and we'll all share this part of the day. Oh and we're taking a picnic' or whatever food arrangements are' x

I think it's a bit weird to take the 2yo, who won't be on most of the same rides, then say the other boy's brother can't come. We only have one child, but I always ask the other parent what they want to do with the siblings, because they are a family. Can you just explain to your son that it's a trip out so everyone comes?

the dad should just take the sibling and the friend go with you. That way no one misses out and the son isn’t having his trip hijaked

weird otherwise 😂

Good point. The man may not be great at communicating. Ask whether it would be a problem for Mark to come on his own. But not in front of the children.

Be brave and say sorry but you promised dis a trip with just Mark and can’t change now. But you will invite the whole family around for birthday cake another day.

just say no and explain your son wanted this instead of a birthday party, he specifically asked to go with mummy, daddy and his best friend. There’s nothing difficult about that.

But it’s a public theme park - he’s going to pay for the boys and I presume look after his small boy, there’s no reason why he couldn’t go, you don’t have to spend the whole day together - you could take your DS and his friend the other dad could make his own way there then go off with the little one for a bit then meet back up. If he was decent enough and polite guy etc I wouldn’t have an issue - I think it’s nice he’s seen this as an opportunity for his boy to spend some time with a friend and him to have a day out with his kids at a theme park - maybe he doesn’t get to do that often 🤷🏻‍♀️

Maybe he thought his younger one could entertain or hang out with your other kid

Or maybe he's just planning on sharing a lift or taking you if he has a bigger car and hanging out with his smaller kid at the same place

You haven't exclusively hired the entire theme park have you?

I wouldn't have let my 8 year old go away to a theme park by himself with another family TBH. I would have made an excuse to tag along as well.

The 'going in one car' thing is pretty weird though. Giving the guy the benefit of the doubt he maybe thinks it's just your DH taking the two 8 year olds?

I wouldn't be comfortable letting my son (9) go on a day out, hours drive and busy theme park with an aquiantance, perhaps that's the reason, and he's just invited himself along to avoid the "I'm sorry but I'm not comfortable letting him go alone" talk.

I mean you can't dictate who can and can't go to a theme park, I get it's your son's birthday treat but does it really matter. You've said it's a younger brother so perhaps the older boys can split off with an adult at some point of the day to ride the bigger rides and someone can take the younger ones on the smaller rides and all meet up for some lunch. i think to make a big deal of a kid going with you is silly, just let it go. The dads paying so it makes no odds to you

You have to stop this over solicitous and frankly controlling man from ruining your son’s big day out. It’s his birthday FGS not a free for all.

Bit of an overreaction to call the bloke controlling just because he clearly isn’t comfortable with his very young child going on this day out, as lots of us on this thread have said we wouldn’t be either. Sounds to me like he’s just trying to find a way that his son can still go without having to explicitly state that he isn’t comfortable with what the OP has proposed and risk creating awkwardness. To be honest I would find it FAR more controlling if the OP told this guy that he wasn’t welcome to come and that they wanted his young son alone in order to fit with the fixed image she has for her own son’s birthday outing, despite the fact he clearly isn’t comfortable with the plan.

Cancel the whole thing and rearrange a different activity when just Mark can come on his own.

Isn’t it up to your son who comes along to his birthday treat? I’d have a word with the child’s father and say he really wanted a one on one with his best friend on his special day. This father’s own concern for the feelings of his younger child isn’t yours…or your son’s. You have to stop this over solicitous and frankly controlling man from ruining your son’s big day out. It’s his birthday FGS not a free for all.

It's OP's DS's birthday treat. If Mark's DF and DB tag along, it stops being a birthday treat. It's not 'creating a problem', it's trying to avoid a birthday treat from being lessened.

So if someone else had taken your child to a theme park for the day, and they'd paid for everything, you'd go to the same theme park and start messaging your child so you could meet up with them - unbelievable!

its a public venue, its not up to you if he goes with his other son. Weird that you are creating a problem when there isn’t one

Tbh n have been in the same position as Marks dad and wanted to come along for a few reasons but mainly because I am really anxious about people driving my child around - myself, DH, and FIL are the only people I am comfortable with doing that and I would not be happy with you taking my child in your car if I don’t know you well. Maybe your driving is awful or your car is not well maintained, I don’t know. But I wouldn’t want to say that so I’ll offer to bring my child and pay for my kids/myself.

I have done this before and left my older child to it, to have fun with his friend, and taken the younger one off. But at least I am there is he gets overwhelmed and I can relax about the travel.

would NEVER ask for a lift though - that’s CFery

I would just say it's fine if he's wanting to go with younger dc but that your ds has been looking forward to a day out with just his older child so you'd like to honour that and go round together and then you could meet them for lunch at some stage/ coffee at the end. And that you've not enough room to transport them all.

It may be that he wants to be around incase his dc gets sick/ lost/ hurt and is happy to treat his own younger dc as well

He's going to use the lack of car space for him not to attend. Then ask if the sibling can attend with you. Leaving daddy dearest with a child free day.