As someone who has a very long history of knee issues (started in the Navy when I fell down a ladder aboard ship and folded my legs up at the knees - sideways...) I know about arthritic knee pain, torn meniscus, dislocated kneecaps, and any other sort of issue one can have with that joint. I've received cortisone shots under my kneecaps every few months for years. Finally, the arthritis got severe enough that I had a total knee replacement on my left knee six years ago. I'm having my right knee replaced next month. I look forward to the arthritis pain finally being gone. Artificial joints aren't a magic fix for chronic arthritis pain, and they carry their own set of issues, but I will be the first to say it is a marvelous feeling to have the constant nagging, aching pain from the arthritis finally erased.
A torn meniscus can be repaired with an arthroscopy. I've had several of them over the years, most recently two years ago on my right knee. I had such pain I couldn't walk more than a few blocks before I had to stop and sit down. The pain was excruciating. My Ortho doc did the arthroscopic surgery and removed the damaged tissue (turned out it was torn in two locations, and the jagged edge was folded under, so was like driving a knife into myself with each step. No wonder I couldn't walk very far!) He also cleaned out the assorted bits of cartilage that had come loose, and smoothed out the underside of my kneecap. After the surgery, I felt almost like new, and that chronic kind of walking pain was gone. I've done quite well since then, but deterioration of the joint, and bone-on-bone contact has increased to the point that the total knee replacement is finally the only choice.
Your husband may wish to ask his doctor about an arthroscopy to repair the torn meniscus. It will certainly alleviate some of the pain he's enduring every day. He may not realize how badly that pain affects his daily life. If you're moving to Honolulu, and will live in Waikiki, walking is something he needs to be able to enjoy. Good luck!
Dave