My father used to hate cats because he had an accident involving a cat. Then we rescued a cat and now he loves her. The main conflict now is that many people dislike coming to our house because of my pets (it’s sad, I know).
Another sad thing that you can include to make your story longer is very sad but it happens in real life. Imagine the family falling in love with this dog and then he dies… it’s cruel and unfair, maybe that makes them not wanting to adopt a dog again, but then MC finds another one and it’s a conflict to make her family changes their mind