This is the fourth time you have asked a variation on the same question, in relation to the same friend who is HIV positive. The replies are the same. But it is clear you are having trouble accepting the minimal HIV risk associated with sharing a life, or living in the same household, of someone with HIV. In fact there is no risk, but given your fears, I agree you probably should not agree to be his roommate. If you continue to consider it, you should first seek professional in-person counseling with someone who understands both the HIV risks and psychological issues you are facing.
Only a limited number of new questions can be accepted, and to leave room for people with new questions, MedHelp permits no more than 2 questions every 6 months on the professionally moderated forums (see Terms and Conditions). This is your fourth since April, and the normal policy is to simply delete such questions without responding. This definitely is the last one that you may post until next January at the earliest.