Went to bed mad

So long story short as soon as I can I'll probably move out and get divorced.. My 3 year old accidentally kicked her brother while they were on the couch and when she tried to apologize he threw her off the couch.. My husband's family is blaming the 3 year old said because she can be annoying and that if she hits the boys they have a right to hit her..This is the 3rd time he has tried to hurt this 3year old...my husband's mom said if my family don't like what goes on here they can help me move out that these boys are always welcome here and they come before the girls.. Then said if my family was to ever call cps or the cops and they take my kids due to the physical abuse then O well they take them.. My husband not once stood up for me. I get kids fight but this kid literally has no patience his parents refuse to seek help with his issues they blame my 3 year old... My family has now suggested I move out as soon as possible..A 9 year old should not be constantly reminded to not hurt a 3 year old. As he has hurt her out of spite.. The first incident was because I told her no and put her time out and she grabbed the cookie anyway and he went and attacked her she pinched him and he cried ..Then while I was in the bathroom two hours later she went to apologize and he tried to suffocate her under a blanket..My husband said its her fault she shouldn't have kicked him accident or not and I'm like so ur blaming a three year old.. He was like they don't do it when I'm home I'm like cuz we aren't home we always out .. I just ended up crying myself to sleep I'm just at a loss