Call cops.?

So my grandparents had a house n they couldnt pay it nomore so my uncle took over n the house was now in his name well hes crazy n last year he kicked them out so they got a apartment n my unclewemt to prison n gave my mom the house n papers n he got out a couple of months ago n went to live with my grandparents again n like 2 weeks ago he found out my lom had sold the house n was getting payed $500 every month n he got mad n kicked my grandparents out n hes now getting the money every month n my grandparents went a couple of days ago to check their apartment because they got a email from their cable company saying that someone was dowloading stuff on the internet n thats illegal n when they went to check he was there all paranoid and asking if they brought the cops n the place was a mess n it smelled like weed n i think he was stealing stuff to with some friend of his n the stuff that they stole was there in the aprtment. my grandma was crying because of how ugly her place looked now so she came back with my mom n so did my grandpa. i was wondering what should i do idk if they want to call the cops on him or what i think theyre just scared. my grandpa has diabetes n heart problems so he cant get mad alot. Also my uncle is 40 no kids no one has been in n out of jail n just been bad. n the apartments are fancy lol so they also dont wanna get kicked out if someone reports the smell of weed.