SO with chronic pain.... Anyone else??

Hey ladies, so my SO has had back and neck problems since a few years back after a couple car accidents. He got surgery in August to fuse the discs and help alleviate some pain. Anyhow, was prescribed oxys for the pain afterwards and when doc decided to cut him down to a level he was uncomfortable with he began going to a pain clinic because they will continue giving him the amount he wants. I don't know much about chronic pain and whether or not he truly needs these pain meds for the rest of his life or if he over uses and may get high? He says he never actually gets a high on them and will sell extra to friends for extra money. Now I am just wondering if he should try other things to get off the narcotics completely or if he actually needs them. He says he will go to a medical detox because he is scared of the withdrawals and will make the effort to not use them at all. He even said he is up for trying medical THC or something. Any advice on how I can help him through this or what I should expect him to be actually taking for chronic pain? He still has to get his neck checked out and possibly another surgery for that... Sorry so long and probably confusing!!!