Inlaws how do I deal with them?

Here's the situation so my sister-in-law and her fiancé moved in with us until they get on their feet. Then along comes the fiancé brother and his gf/fiancé/ baby mama and their two kids (who were originally not a part of the plan to live with us) at 6am one morning saying they needed a place to stay not really asking just assuming since sister-in-law told them it would be ok... recently the sister-in-law has also been making decisions about my husband's and my pets. Giving our chiwahwa-mini greyhound mix 5+lbs of food (because he's "too skinny") and then when he eats it all and has an accident they get mad cus it smelt bad and instead of cleaning the area and his bedding ...they throw his bedding and the reusable (waterproof) floor protector away and chained our dog outside. A couple days before that we asked them if overnight they could watch our dog (they said they would) since we were going out of town for the night ... Well they decided to take our dog(without asking us) over to the inlaws and leave him there... This may be my hormones over reacting but how am I supposed to feel when they made decisions without asking how we felt??.....my husbands is upset too but doesn't know how to feel right now either...