Hi --- Not sure of the specific cost in the transfer of equity itself, but they have to have that enduring power of attorney correctly registered with the OPG first, to allow them to legally sign any transfer of equity documents or in fact act in any larger property transactions on behalf of your FIL.
In between the registration being processed and during the transitional period, they are only entitled to use limited powers to act on his smaller necessary short term needs, like safeguarding his assets or paying his bills etc..
They need to get that EPA officially registered first with the OPG, to safeguard themselves .....and should check that they have the court of protection's approval and permission to conduct the proposed transfer of equity beforehand .....also acting fully within the scope of their powers granted by the donor, otherwise the attorneys could possibly be seen to be acting with a conflict of interests. !
If unsure, see their Solicitor because this can be a very complicated subject, especially since all the rules were changed last year when new lasting powers replaced the older EPA.