Durable Power of Attorney etc

I apologise if I am asking a question in the wrong Forum.

I am dual citizen UK/USA.  Sponsored US husband of 34 years to live in the UK - ,submitted ILR (SET M) application OCT (?) 2021. 
We still have a home in the USA but live in England and my husband is currently quite ill (hospital) and probably suffering from dementia of some sort.
I am in serious need of advice regarding our Wills,  Living Wills,  Durable Power of Attorney for both Health and Property etc all drawn up in Florida in 2010.
I may have to invoke one or all of them in the very near future; is there anyone in this group that could share their experience in this area or offer me some advise?   
I "think" that as both USA and UK are Signatories to the Hague Convention on UK and International Wills that the Florida Wills, Durable Power of Attorney (health and property) and Living Wills might be accepted in the UK but.........

Fellow members, you have expertly guided DH and myself thru the Spouse Visa immigration process to our  ILR submission I hope one of you can offer advice in this situation. Many thanks

I'm sorry to hear that your husband is in hospital...
If he has Dementia and now lacks capacity, then the Court of Protection is the route to take for LPA Property & Financial Affairs & LPA Health & Welfare. If ‘capacity’ remains, then you may file yourself or via a Solicitor in England or Wales, (should you reside in those parts of the U.K.).
International Wills looks at assets / residual estates on death. There are provisions for Inheritance Tax etc under the U.K & U.S Estate agreement, (a complex area). However, the FL Will that you have from 2010 I feel would be unproven under English jurisdiction in the case you now face. 
So called ‘International Wills’ are fraught with problems, (so I understand) and the very best option would be to have both an FL and English Will. Critically, ensuring that one does not override the other.
I’d without hesitation get an English Will drawn up ASAP, address all local assets and the LPA etc. Be sure to avoid any ‘Foreign Trusts’ though as these will require 3520 and 3520-A IRS filing, certainly not forms for the faint hearted.
I hope this helps…