The easiest way to skim from a large account would be to either inflate billable hours or inflate hourly fee. Do lots of "Review File" entries and review that file extensively. Daily.

If the people in question do not know or understand the extent of their assets or the natural objects of their affection, then they're probably ripe for a guardianship of their property. Note that sheer stupidity or poor investment decisions or a tendency to spend lots of money on in ways that you don't agree with is not necessarily incompetence. That said, if they're truly incompetent, they might need a conservatorship -- terms and applications vary widely between the states and you really do need to talk to an attorney in your jurisdiction. A power of attorney might suffice in some cases -- full conservatorship might be necessary in other situations. You CAN ask questions of the attorney and accountant IF you've got some sort of authorization from the person in question. IF. Otherwise, attorney/client privilege prevents them from answering much of anything.

Other than that sort of action, you've really got no right to poke around in their affairs.

See an estate/probate specialist in your jurisdiction.
Cyn