The attorney who is drawing up the irrevocable trust should be advising your mother, the Grantor, that she has to relinquish power over the trust to the trustees, once the trust is established. She can stipulate certain provisions in the trust to control your sister’s proceeds which the trustee(s) must honor.
To help maintain family harmony, it would advisable for your mother to consider appointing a trustee(s) that are not family members. An institution can be hired or an individual such as an accountant. Trustee services come with fees, so the choice should be researched carefully.
Susan L. Easthope, CFP
Disclosure: For informational purposes only. Not to be considered investment, tax, or legal advice.