how to ID an overseas client?

I have been approached by the adult child of an overseas individual to take on their parent as a UK tax client. They have been referred to me by an existing client. The parent lives abroad (not in a high ML risk country) and is very ill, so will not be returning to UK. Adult child who is in UK has power of attorney. I have no reasons to be suspicious. In order to meet ML regs, is it sufficient to:

-meet adult child

-see (and take copy of) original POA

-see (and take copy of) passport of adult child

What would you do?