THEIR Attorney, as you know, represents THEM and their best interest and is bound to confidentiality HOWEVER theres no harm in making inquiry and since youre already a trustee and are looking out for their best interests (NOT your own) I see no harm in asking. If the attorney does not feel comfy he will let you know not a problem, be up front and tell him your wishes and your concerns, cant hurt.
Again, a trustee or a guardian or a POA is a strict fiduciary and none of those grant them the power to take things for themselves, although that has happened grrrrrrrrrrrr
Actually if you are the Trustee YOU probably (depends on trust) HAVE A DUTY AND OBLIGATION to make inquiry,,,,,,SO GO SEE THEIR LAWYER IS MY ADVICE and don't do anything Billy Bobn or Bubba say was what they did as each situation is different. Trusts and POA and Guardianship is NOT something a lay person can help you with very much, nor even a profession UNTIL THEY REVIEW THE TRUST AND THE SITUATION AND THE LAWS OF YOUR STATE
I practice in this area and no two estate plans or wills or trusts or guardianships have ever been the same........Whats perfect for Billy Bob can be the opposite of whats best for Bubba
Best wishes n God Bless