How to deal with a familiy member living with you?

Ok here is the problem my husband owns a home from befor we got married and we moved back into it a few months ago and his cousin is staying here he is leaving in two months there is two of them but i am only having a problem with one. ok problems started about two weeks ago when we lost power that day i had went and bought my 2 year old daughter a barbie laptop and i had taking the back off and laid it on the kitchen counter to put batteries in then the power went out and we all just went and sat outside and waited for the lights but they didn't come back on till after everyone went to bed well the next morning i woke up and looked all over the house for the back to the laptop and it was gone and noone and i mean noone else was in here that night but when we got up he was out here cooking so i just let it go but we both know that those things are very expensive and then about four days ago i had left and went to the store and went shopping and came home and he had thrown away pieces to my new air conditioner i think that is also what he did with the back to the laptop i got the air conditioner pieces out of the trash but i again just let it go but he keeps doing things like that he has a son but he is not here with him i think he is jealous because my kids have things not alot but we try to get them nice things.Yesterday i was on the computer and he took my daughter outside without asking me and i went out there and did not see her or him and got very worried they were over at a neighbors but i was worried she is only two and i don't want her outside without me maybe he was trying to play with her but i don't want someone taking her out without asking me. then this morning i woke up to find my clean white clothes that i had in the dryer on top of my husbands very dirty work clothes that were covered in insulation and metal and dirt he had taken them out to dry his socks now i wouldn't care that he took them out but i cared that he took them out and my daughters white baby blanket was in there and put them on top of dirty clothes. I don't know how to handle this i know he is leaving in two months but i don't know what i should do. I should also say he is almost 30 and has a wife and son so he is not a young kid. Please i could use some advice i have started to get mad at my husband even though it is not his fault and he trys but i don't want to blow up at his family i am the kind of person that has a big heart and very calm but this man is driving my totally crazy. I need to know how to handle him for the next two months and not blame my husband for the things he does please i need some advice. and him leaving is not an option so please don't say that.I do not want his family thinking i am a mean but i do not want them to think they can run all over me. also we do not have lots of money so i cant afford to buy things for them to get thrown away.