What kind of Charitable Trust?  A Charitable Remainder Trust, required to file Form 5227?  How long has she been your client, and what has been filed for 2022 through 2024?  (I would be waiting for those shoes to drop.)  Or is at a trust that files Form 1041?  

What authority does the son have to manage the trust?  Generally, trust powers can't be delegated with a Power of Attorney, absent a specific provision in the trust document that permits it.  Sounds like you might have a real Pandora's box that turns into a can of worms.