In law issues

I feel like I have a million problems with them, the major problem is that his family has no respect for anyone’s time but their own. His family members are all addicted to alcohol and drugs, his uncle (with a family) is a self admitted drug dealer or as he says “business man”. His grandfather has grabbed me in appropriately and says sexual things like calling me sexy, saying I should spend the night with him etc. Every time my fiancé is near them, he thinks irrationally, or goes off the grid for hours at a time. For example, his uncle has asked him to do illegal things such as cashing cashiers checks of drug money, or a crazy idea such as him going to Hawaii without me after we have a newborn for “only 10 days”. In every situation I’m uncomfortable with his family and ultimately I’m not invited to go anywhere or do anything with my family yet he’s invited or self invites himself to do things with my family always. His uncles girlfriend makes sure to pry her way into our personal business and texts him 24:7 in long paragraphs about her personal problems. My SO knows how I feel but says he’s put into an uncomfortable situation what do I do? He went to dinner at 4pm and has been off of the grid since then with his phone shut off.