Portable oxygen machine

I would appreciate any help that you guys can donate to get Jim a compact light weight portable oxygen machine. He currently has portable tanks which are to heavy for him to get around  And add to his balance issues. The company that his insurance goes through is out of them and his insurance will not help with the purchase of one. This is the last thing I wanted to do. Asking for help is not easy he’s just finally letting me help him. Thanks everyone for looking at this and helping if you can.