AIBU to keep my sister’s former dog after she moved back?

Are Both homes equal for the dog? Similar quality gardens, local walks, time with/without you during the day?

I voted YANBU as you made the rules clear. However, I would do what's best for the dog.

If you did get a new dog your kids would cope with the loss quite quickly.

I would offer to fund sister getting a new dog, on the understanding that no matter what happens she will never rehome it.

If I was in your situation there would be a rift in the family whether I gave her the dog or not because if I was pressured into handing over a pet that she had given to me, I would have little if anything to do with her going forward. I would also be casting a critical eye at the other family members who joined in on her behalf.

In your sister's shoes, I might have tentatively asked how you would feel about giving the dog back but once it was clear you didn't want to I would have got my children a new dog. They would have the best of both worlds their - a dog of their own and seeing their old dog when they visited you.

Definitely keep the dog, it’s absolutely in his best interests. He’s not a commodity or a soft toy.

I completely understand that your sisters DC will be unsettled and upset following a significant period of change, but that’s not the dogs fault.

They’re also saying that as the dog has only been with us for 7 months, we should give him back as it’s not long enough for him to have settled.

And how old is the dog? And what breed? That's completely relevant here.

I disagree with others that after 7 months a dog will be 'secure' in it's new home. I've known dogs that after 5 years still react like puppies when they see their original owners (I rescue, so I see re-homing a lot).

But honestly, regardless, I would show some compassion. She's lost her husband. Her kids have lost a dog. And the dog is their family. There are often very good reasons (as the wife of a diplomat, I have a lot of empathy for your sisters circumstances) why people leave dogs behind i.e if the climate is not suitable for them. It doesn't mean we don't care.

Not the ddogs fault her plans changed. He's happy in his new life.. aren't the family bothered about your dc ?

The ownership of the dog was transferred so you are not obligated to give it back and can't be forced to. If they wanted to keep the dog, they should have arranged for it to travel with them.
I have no advice about how to manage the rest of the family, sorry. It may well sour your relationship with them but that doesn't make giving up the dog the right decision. It's a sentient being and can't be just used as a bargaining chip for the sake of family harmony. A decision has to be made in the dog's best interest which is not to uproot her all over again.

How old is the dog, and how long had they had him before they left ? I think I’d return him, console your children they will still get to see him, and get a dog of your own.

I’d be keeping a tight hold of the dog in case any visiting family member would decide to grab hold of the dog and bring it back to your sister.

After seven months, a dog has learned to feel secure in its new home and it is very unfair and unkind to move it again.

I’d keep the dog with you. You had an agreement, ownership was transferred and that is that. One set of children are going to be upset, why should it be yours, when you knew this would happen so agreed to take the dog on the understanding if would be permanent.

I wouldn’t be that surprised if they always planned on asking/pressuring you to give the dog back when they got back. If she’d stayed 3 years I think they’d have still come back and said the same about it helping the children settle back etc etc.