All perfect praise be to Allah the Lord of the Worlds. May His peace and blessings be upon our Prophet Mohammad and upon all his family and companions.
When a human being gets sick to the extent that he/she is unable to spend his/her money in the correct form, then it is the duty of those in charge of him to ask the judge to put him/her under interdiction. On his part, the judge appoints a guardian for this person and by doing so the general power of attorney gets cancelled because acting on behalf of the interdicted becomes the right of the guardian.
As for dividing the property of the interdicted amongst his heirs, this isn`t permissible so long as he is alive and no portion of it may be taken save in accordance with the teachings of Sharia. And Allah The Almighty Knows Best.