Suboxone is what is commonly used in detox. 7-10days is the average detox time, depending on what you use and your insurance. People will go into withdrawals if they take benzos (xanax) or possibly alcohol while on suboxone. It sounds like he is fighting the recovery. Threatening suicide is probably one of his old tactics to manipulate. My AS does it all the time and apparently so do a lot of addicts.
Stay strong. figure out what you want for yourself. he is an adult. You are not responsible for him. Despite how you may feel about him, you need to decide how much you're willing to take.