Yikes. This situation is no good. What he did - and did using your credit card! - trouble, trouble. It's easy for me to say...but, given his history, I expect that as soon as he recovers from his surgery he'll be right back with the porn, hook-ups, and so on. This cannot end well for you.

In California the law says that anyone (even if the person has not paid rent, ever) who has stayed in a home for 3 months or more (received mail there) cannot be kicked out. An eviction notice must be served by the person who allowed the other person to stay in the home. Not only a difficult and miserable situation, but potentially dangerous if the one being evicted is prone to violence. So I don't know what the law is in your state, but you can easily check it out on google.