You need to get POA, Health Care Directive and Living Will while he is competent to sign paperwork. It is good advice for married people to have them in case of severe health issues or injuries.
I have registered my PoA for my husband with the bank and other financial organisations, also with his private pension providers, state pension, tax office. I am working my way through organisations as issues crop up.
that's how this works also ,he can still make his own decisions but when unable i will ,also having poa is easier with phone calls concerning perscriptions etc ,they always want the person to give the o.k. to talk to you, now i don't need the ok. he never took care of this anyway.
The one thing I've not seen in this conversation string is the importance of changing your own legal representative for financial had healthcare decisions. Like me, you may have named your now incompetent spouse for this - yikes! Very important to change that ASAP!