Justine and Justin are twins and are very close. Justine is $70$ ?years old and is preparing her Will with her notary. She asked Justin if he would be willing to manage and administer the finances per her instructions within her Will for one of her beneficiaries, Mary $($ Justine $\text{'}$ s best friend $)$ ?who has Alzheimer's. Justin would be the $\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_,$ ?as someone responsible for the management of Justine's assets held in trust for Mary.