To stop visiting if my sister brings her dog

So what? Do you know how annoying other people’s kids are?

So your sister clearly does leave the dog if she and her partner work full time and she goes out every Saturday night while he’s at work. She’s not taking the dog clubbing! So she can just leave it at home for a few hours.
I would simply stay firm and refuse to go if the dog is there. Let them scream and shout and stamp their feet. They will have to agree to either leaving the dog, or having a cage, or any of the other reasonable suggestions. If not they won’t see you or the kids

I know how your friend feels.

I was bitten by nans dog when I was 5 and I am petrified of them. Everywhere now being "dog friendly" puts me on edge. Im now 32 and there a few of my husbands friends who have untrained dogs and I simply refuse every invitation and explain "as much as I appreciate the invite, I'd feel very nervous around the dogs"

All you can do is stand your ground and when they mention it, again, explain that until it's calmer/trained, the kids cant be around the dog.

OP, in your shoes I would just phone my Mum and tell her that it's absolutely no use her complaining that she's not seeing her Grandkids, when she is prioritising your IRRESPONSIBLE sister's need to treat an animal like a human baby. Your Mum is also being irresponsible, as she's clearly encouraging your sister in this, and in my opinion neither of them deserve to spend time with your beautiful children if they're not prepared to put THEIR welfare first.

I am a dog lover, but there is absolutely NO WAY that I would allow an untrained puppy to run loose with a young child and a baby in the room. The fact that your sister's pup has already bitten your 4 year old, is an absolute disgrace!

Your idea of caging the pup is a good one, and the most sensible answer in my opinion, as it will also give the pup a safe place to retreat to, when your baby becomes a toddler that is likely to chase it, pull it's ears, tail, etc.

My sister, who was also in her 30's did exactly the same thing, bought a pup as a handbag dog, didn't train it properly, and ultimately it became a nuisance to her, when the novelty wore off, as they worked full time. It ended up with me suggesting that I take it off her hands, and she couldn't get it out the door quick enough, which is an absolutely DISGUSTING way to treat a pet. The dog became a well trained part of my family, and we were heartbroken when eventually the time came to put her to sleep.

One question, can your sister not have children, as she'd be a far better mother than she is dog owner?

if my sister said that to me i would be very clear: if the puppy does that i will punch it in the head until it stops moving.

Time for your family, OP (as in you, DH and DCs) to set up your own family sunday routine that does not include going to your parents for lunch. See your parents another time when your sister isn't there, or in another space. Be very clear that your sister's dog is not allowed in your home/garden. And that if your mum does come to yours, and then invites sister & dog too, that you will send them all away again.

They're kids FFS!

I wouldn’t go if it was bf and would suggest visiting at different times. The dog can be left at home (in a crate) for short periods 🙄 why can’t they leave it behind, how far go they travel?

Did they have a conversation with you, considering your concerns for your children at all?

Are you going to let your mom guilt trip you into disregarding your children’s safety and comfort?

Set some boundaries for you kids. It’s only going to get worse as the dog gets bigger and you mom learns more and more that it is okay to disregard your concerns. She can come visit her grandchildren in your home. On your terms.

We had this situation. In our scenario the dog is at least trained. But they take the dog everywhere with them. 6 years down the line. It was a covid puppy so has servere separation anxiety. To be fair id rather the dog come. Its better behaved than its owners.
I think in your situation there has to be some boundaries. Your child has been bitten. I dont know how your parents and sister can be ok with that.

i think you and your sister should alternate weekends. At least until the dog is “better trained”

she (your sister) sounds exhausting

a real shame for your DPs to be caught in the middle of this. Yanbu. Your sister is.

You are not being unreasonable.
Your child is scared, being bitten is a big thing for 4 y.o.
It sounds like your sister is very immature and selfish and doesn’t get it. So I would try to stay calmly and just focusing on your eldest being scared and baby not being able to go on the floor. Don’t give them solutions, just ask them how they think your eldest felt about being bitten.

Your sister has to get the dog trained, that’s not good and she needs to start now with saying no when it jumps up. It will be much kinder to the dog in the long run, dogs can’t bite children.YANBU

That would be enough for me not to be around her at all.

What kind of person calls a 4 yo a wimp over their dog biting them?

She obviously thinks the safety of your children matters less than her dog.

She might feel the same about your kids?

So they can leave their dog alone for chunks of time when they're working but can't to avoid it biting your children? And you're to blame for your parents potentially not seeing as much of your children? Wow. You are not the unreasonable one here OP. Have you heard the phrase "let them"? Let them kick off. Let them be annoyed. Let THEM find a solution to this. Its not a problem of your creation.

I don’t know what to tell you. Obviously you are not being unreasonable. There’s clearly a range of dysfunctional family dynamics going on here and neither your sister nor your parents can be trusted to act reasonably or sensibly. Sad, but it’s on you to state your reasonable boundaries to keep your children safe and not bend to them. Good luck.

I have a dog.
I have kids.

Yanbu.

I think the reason you are getting such pushback is due to the enmeshment with the CORE family.
You dont go to your husbands parents and Dsis doesnt to her boyfriends parents EVERY Sunday do you???
Why is that?
Hint: its not just due to distance.

Your DM, Ddad you and Dsis are/were the core unit.

You having kids was fine initially as it didn't upset the natural order and your kids could tag along and / or be treated as communal property of the core family.

Back in reality... You now have your own family whose safety you are ( rightly) prioritising.
This challenges the "Core family unit" and preservation only that is paramount and the no 1 priority for your mum and sister.

Your sister is also most probably the favorite.
Why else is your mother choosing to let a dog piss and shit on her floors each week instead of seeing her GC
or taking you up on any of your v reasonable offers.

Separately and possibly unimportant...
I notice your dad doesnt feature much in this.

Separately and unimportant
Your sister sounds like she isnt training the dog if there are multiple indoor accidents.
And she can go to work / cant train it in the week or bother to use annual leave... but it cant stay home alone or with the boyfriend for 2 hrs... puh-lease

I'd be saying a lot of things like

"I'm sorry sister isnt willing to try any of the many compromises I've offered"

"my children's safety and comfort will always come first"

"I'm sorry your inflexibility and prioritisation of a dog means you are seeing less of the kids. I know they'd love to see more of you"

OP isn't looking to punish the dog, just to establish a way of socialising with her parents that doesn't involve the dog until it is better-behaved. Her family are resisting this. They are prats. The dog deserves better, too.

Puppies bite, they all do, it's got nothing to do with training at such a young age.
And because they have very sharp baby teeth, they often draw blood. My hands were like mince for months when my dog was a puppy.

Now, it's not because it's normal that it's okay, especially with such young children. With puppies, beside training, the key is to manage the environment, by using crate, puppy gate, long line etc...letting a puppy run loose with small kids around is just stupid and irresponsible.