AIBU not to go to brother-in-law’s 40th holiday because of kids and my own reservations?

The 18 months old is too young to leave. That is your reason for not going, in its entirety (as far as your BIL is concerned). He could argue with 'feelings' and 'safety' and 'birthday'. He can't really argue with baby's age.

So "thanks for the invitation. I'd love to be joining you, but the littlest one isn't old enough to leave for a week, yet. I know that DH will celebrate with you for both of us, though"

"oh and they said kids aren’t invited! To be fair their ow kids aren’t invited either. So it wasn’t an option bringing the babies."

"I know my DH, my brother and sister in law will all be offended if I don’t go"

Honestly, they sound insufferable. They want to command you to:

1. Pay a fortune to fly there
2. At a time of their choosing (unlike if you were going on holiday)
3. For a length of time of their choosing
4. Without your two young children
5. And they want to act all offended if you don't want to be commanded.

And I don't care how close your husband is to his brother, he should be a damned sight closer to his own wife and children.

No. I did leave my 18 month old for a 3 day hen do and I will leave him at 2.5 for 5 days for a wedding in Asia but he will be with his father. Neither of us is comfortable with the idea of both of us leaving him. It would be very confusing and distressing. Those ages don't travel well anyway, a flight to South America would be a pain.

What sort of idiot would even issue an invitation for such a long time to parents of such young children without including the children?

When you turn it down, don’t say anything about local safety, just say you can’t leave the children for that long.

What happened to a night down the pub?!
If they want to go away to celebrate his 40th, thats great. But pretty unreasonable to expect you to leave your young children. Its not exactly a short hop on a plane to get home either.
I wouldn't go, and I wouldn't leave my child on their birthday.

I wouldn't leave such young children for 5-7 days and I think it's rude of your in-laws to try to insist. Let them be offended.

Besides, I disagree with the idea that a 40-year-old's birthday necessitates a five day celebration whereas a 3-year-old's doesn't matter at all! OK, the three-year-old won't know exactly when his birthday is, but when you've only been around for three years, birthdays can be really exciting. I wouldn't want to miss my young child's birthday.

I wouldn’t go in your shoes unless I could bring the kids and then leave them with babysitter on the party night

Absolutely not. When DD was 3 I had only ever left her with GPs for one night at a time and I think that was maybe only twice. In each case we were still in the UK just a few hours drive away.

Your DH can go by himself. It's his brother after all.

Another who wouldn't go that far, for that long, with kids that age. Or for one's birthday!

I definitely wouldn't go. The children are far too young to be left that long, let alone missing his birthday.

I love a destination wedding/overseas party etc but I wouldn’t go away over my DC’s birthdays and my youngest is 25!

I wouldn’t go. Let your husband go alone. I’d never have missed any of my children’s birthdays and your three year old will be fully aware it’s their birthday, mine were at that age, yes their memories fade but on the day they know!

I definitely would not leave kids that young for that long. I left 3 yo Dc with their Dad for 3 days for a work event and that was more than enough.

Plus, I am not normally an overthinker about 'what might happen' but 3 weeks ago no one imagined that flights from Thailand to Sri Lanka to the UAE would be cancelled leaving people trapped and stranded. Trump only has to randomly turn his attention and a few missiles back to Venezuala and the airspace over S America could be the same.

If they invite people with small children they can hardly be surprised if you decline.

I’m pretty chilled and would leave my dc now (ages 14-18) but would still feel guilty. Absolutely no way would I have left a 3yo and 18mo, go to another country and miss my dc birthday. Them asking you to do that to suit them is outrageous imo.

I wouldn’t be going away and leaving such young children for a week. Given your choice, I’d rather offend BIL than upset my children. Your DH can go to the celebration on his own.

Are any of the family originally from South American or are they ex pats living there with a certain lifestyle? I’m asking because it seems odd not to include your own children at your 40th birthday celebration!

When they come to visit you, do you insist their kids stay at home?

I doubt bil will give a shit if you aren't there...

with these type of posts I’m usually one of the people encouraging mums to take the trip, I regularly take short trips away without my children, but under these circumstances there’s no way I’d go. It’s your BILs choice whether or not to have a child free event, but it’s your choice to then decline the invitation. They’re too young, it’s too long, and too far away (in my view!). Tell him you’ll definitely be there for his 50th!

Presumably your DH will be going?

They don’t have the right to be offended when they won’t let you bring your kids for such a long journey.

They surely won’t actually be expecting you both to come?

its like when my cousin got married in Australia when I was going to have newborn twins. I was invited, but she knew I wasn’t ever going to be able to make that trip at that time. It was a polite invitation.

if they’ve have a brain between them they’ll know that you’re not going to leave two young children for a weeks travel to another continent for a birthday party.

A week is a long time to celebrate yourself. I'd send DH for 5 days max.

They can't expect you to leave 2 little kids behind for a week, it's an awful lot of childcare for the GPs too. I wouldn't go. Would be different if it was a weekend. And to miss a birthday too, little kids' birthdays are special, it's for you to celebrate as well as the child. It's "week long overseas hen do" territory, a bit of an ego trip.

i think you need to do what is best for you. There’s no point reluctantly going if you will be on edge and worried and guilty that you have left your child behind.
why can’t you all go as a family? I know there may be adult only events whilst out there so you may not all be together all of the time but it would alleviate the issue if the distance and how long your expected to leave your children for.
lastly, is this likely to cause problems with your ILs? Are they likely to hold a grudge about it? (It’s an invite, not a summons but worth considering)

I wouldn’t feel comfortable leaving children of that age for so long either. Even if I wasn't so far away.

I can’t imagine not inviting my nieces or nephews if I was in your BiL’s place