Go for it? Love, are you mad?!!! The rights and wrongs of tenants being allowed pets is not the issue. The point is that it IS a breach of her actual tenancy. Getting a dog would give her landlord the perfect legal right, if they so chose, to evict her and the children!!! The council would have no obligation to house them.
Ok, maybe us tenants ought to be allowed pets, but if the legal agreement prohibits that, and you choose to break it, you are potentially making your children homeless.
That can never, in a month of sundays, be the right thing to do.
And for what? I should be able to have a dog, so I will have a dog, it's unfair that I can't.
Yes. It is. And?
You can't work on the way these things ought to be, you have to deal with them the way they are.
Imagine going to court to try to fight the eviction.
"I know I signed a contract, but I think it's unfair. Why shouldn't I have a dog?"
I give you one guess how that would go!