executing a will

[NettleTea]

my partner's mother died

she and her husband had mirror wills with each naming the other as executor, and with the 2 children named if spouse had died.

FIL is still alive but he has early dementia and actually is not capable of executing the will

solicitor suggests that probate is ;probably not needed as its a simple transfer of everything to living spouse

solicitor asked if DP had POA as it can get expensive for FIL to appoint DP as deputy - but is this only if they had needed probate? If its a simple case of transferring some shares can DP action it?

Both solicitor and accountant seem happy to take instruction from DP but Im aware that FIL is named as executor and hasnt appointed DP to do it. He has agreed to POA and we will get that done.

So can DP go ahead and act as executor given no need for probate and while waiting for POA to be put in place?

If your FIL has capacity, but just can't do the executor bit (and being judged to be OK to still do a POA would indicate that he does have capacity), then he could sign a deed of renunciation to say he doesn't want to do it. Then as your DH is NOK, he could take over.
I think you just lodge the renunciation with probate when you do the application.
Whatever, you need to do the whole IHT and probate process even when it is being left to the spouse. It is all really straightforward and online unless its a very big estate. NB - am no professional, but have done IHT/probate for both my parents in the last month, and in fact just finished up mums probate application this morning

Oh, and you can call the probate helpline, and they are very helpful

I wonder why you have accountants and solicitors involved? Is there a lot of money besides the house?
I agree with CMOTDibbler I've done both my in laws estates, my brother in law, my father and am just doing my mothers. Didn't use solicitors for any of them.
If your FIL has capacity but just doesn't feel able to do it all himself then your DP could handle it with FIL just signing where appropriate.
The easiest is a straight mirror will. Easier still if money and property in joint names.
I also found the Probate office very helpful and the IHT part of HMRC.

family solicitor holds the will
bugger all money in a savings account (less than £500)
shares held within a Ltd company thats in a sector that is exempt for inheritance tax, and which owns all the land and house. But need an accountant to do yearly tax returns by law