Ipad backup

Mum (aged 90) has a2010 iPad , trying to back it up to my pc so as to update it. It is asking for Apple ID and password, she has no idea - she has given me a few passwords, but none are working. I am afraid I have lost everything from her iPad. We plan to buy her an updated iPad but hard to get an affordable one with a sim due to high demand at present. Can any one help please?