Special Needs Trusts

Dear Len & Rosie,

I am the trustee of my recently deceased mother's trust, which includes a Special Needs Trust for my disabled sister, Judith.  Both before and after our mother's death, my sister has rented a property owned by the trust.  As trustee, can I pay off the mortgage on this property and turn it over to my sister while staying in compliance with the terms of the trust?

I am particularly concerned about the following passage in the trust "For the purpose of determining Judith's eligibility for any public benefits, no part of the principal or undistributed income of the trust estate shall be considered available to her".