The short answer is maybe. What you need is an accounting of the funds in order to determine whether there is a reasonable basis on which to hang a charge of breach of fiduciary duty. Most Social Security lawyers with some experience will be qualified to take on this type of challenge.
Possibly. Ask the agency for a full accounting. If they fail to provide one or they can not explain discrepancies you may either hire a Social Security attorney or contact Social Security and file a complaint with the agency. If you decide to do this without help of council, make sure that you are very clear with what you feel is amiss. Generalities will not be useful in this situation. The more proof you have of malfeasance the more likely that action will be taken.
If the amounts are minimal it may not be worth your time to pursue.