It can help alleviate some pain yes, as I did that by losing 84 lbs and took up hiking trails.
Movement such as walking , hiking ,swimming helps the joints.
I could not use a normal bike as I injured my back years ago , but with these new Fat bikes or spring suspension bikes it helps alleviate impact to the back.
Sometimes the injury is Arthritis and if so the can use pain patches that stick on like bandages and deliver med for pain and or heat on those areas while active etc.
I became a better healthy person after losing 84 lbs ( 8 months on Slimfast twice a day).
I hiked up mountains, hills, roads, and photographed all along the way. It became a pleasant hobby that I still do three years later.
I hurt my knee in an injury ( tendon) that took almost two years to heal enough so that Now I again am on diet ( SF) to lose that weight from inactivity and long winters. I feel much better from losing weight ( down one size already in one month) and continue to work on that goal.
My back feels better as no undue pressure is pressing on it anymore, I feel lighter.
So weight loss does help, but only IF that person really wants to go that route.
It does not work to have others pressure one to lose weight. Its a complete lifestyle change to eliminate bad habits and bad choices in foods/snacks.
Drinking alcohol does more damage to our cells and causes weight gain as well.
Some people are there own worst enemy by sabotaging their health.
Good luck to those people in striving to be better and healthy.