@lovinglife I am so sorry to hear that you were robbed by your cousin. I hope your homeowner’s or renter’s insurance will cover it. Have you thought of filing a police report, specifically naming him as the suspect? Don’t worry that you “can’t prove it.” On the police report you can say that you have very strong reason to think he is the thief because of the comments he made, and the fact that he is now avoiding you. The police might search his home to see if any of your property is still there.
This sounds like thousands of dollars’ worth of property, which is felony theft. You might be able to check Craig’s List to see if your stuff was sold on Criag’s List by your cousin.
My guess is that your cousin is a drug addict because stealing from relatives is what drug addicts do. Again, I am sorry that this happened to you.