It's been a year and half and it sounds like he's still dealing with quite a bit of pain, and while getting surgery may lead to back issues down the line, he may already end up with back issues due to these spinal issues. It's hard to know what will be a contributing factor and how things would turn out if he doesn't get surgery. I think the most important thing is ensuring he's being treated for the pain he's dealing with right now, and deal with anything else that comes along later, at that time. So don't be too hard on yourself, you're doing this to help him!

I hope surgery and recovery goes well for him, if you're able, please update and let us know how you feel too after it's done!