The first question I have is what type of arthritis does your mom has? From the description you gave, it sounds like rheumatoid arthritis (RA) as opposed to osteoarthritis (OA)(aka degenerative/wear-and tear related arthritis). It is important to know the difference as the treatment for the two are different. Were the monthly shots corticosteriods, plaquenil or methotraxate? I am not sure why the shots are being stopped. Hopefully, the new doctor is a board certified rheumatologist.
If it is RA, then for the time being, using low dose ibuprofren or aspirin should help temporarily with the inflammation.