The electric can openers are not that expensive, although I don't know your budget. Also, sometimes just buying a new standard can opener helps. The edges loose their sharpness with time, and it gets harder to open cans. OXO Good Grips makes a good can opener, and it is designed for people with arthritis or who have trouble using their hands. That is the type of can opener I have.
I generally do not buy food in cans, though, as for me they are hard to open. I get other types of food instead, so I avoid the problem. I'm sorry your family is not supportive. Thinking of you.