I recently had to deal with this here in the UK when selling my mother's house. She's 94, far into dementia and bed-bound, was a stay-at-home mom all her life. She had no photo ID of any sort, and since she'd been in a home for quite a while, no utility bills or any of the other things needed to prove identity in the modern world.
It took quite a while to work out something that would be accepted for the title transfer.
FWIW: buying with owned funds is easy, selling is hard. Sellers don't really care about identity verification as long as the funds are good. OTOH, buyers/lenders/title insurance issuers do want the sellers' identities to be solid, because if they transacted with the wrong person, they are going to have a bad day. Lenders probably also want the buyer to be well identified, because it'll be a mess if not.