Actually, Wylie, the whole situation has changed.
With mental capacity an issue, I presume you are acting under an Enduring Power of Attorney (EPOA). If so, your sole legal responsibility (in administering the person's affairs) is to act in the best interests of the person who gave you the EPOA.
This may not necessarily be what was planned or agreed to when the person was mentally competent.
For example, I may be planning to give my assets to my children. This may be documented and ready for implementation when I become incompetent. I have given an Enduring POA to said kids. If they were to proceed and transfer assets into their name, even though it had been my plan, from the advice I received I believe they would be quite seriously in breach of their legal obligations under the EPOA.
We had to go into all this rather thoroughly when my mum's Alzheimers meant she entered a nursing home, leaving us with the issues of bond payment, house sale, investment decisions etc. We took legal advice before taking any action, and had to change our intentions somewhat to ensure we fulfilled our legal obligations under the POA.
To put it VERY simplistically, my sister and I were told we had to ensure all assets and monies were available to be distributed under the terms of her will when the time comes to administer her estate, or to establish that the money had been spent to her benefit. Due to incompetency we know her will won't be altered which ties our hands somewhat.
However, I am aware that legal opinions can vary so other legal advice may differ.
Marg