My experience with my elderly mum is that she’s finding it increasingly more difficult to operate a PC. She’s owned and used one regularly for longer than I have, so it’s a bit distressing watching this regression.
The biggest hurdle is getting through to her that a PC is not something to be feared. You have to dip your toe in the water in order to learn. Maybe you just need to build her confidence and helo her with some basic tutorials. Give her the chance to may a few notes in a booklet so she can refer to this when she gets in a muddle. You just need to invest some time really.
My advice is to become fully au fait with anthing you decide to get for her because you will be the one she comes to frequently for first line support. Also, if you have the same machine at your finger tips, you can talk her through things over the phone. I’ve done this many times with my mum.
I’ve only had limited use of an iPad and haven’t tried web browsing. I’m sure it won’t be too daunting, probably easier than any PC, but why don’t you go to your nearest iStore, have a play with one and then decide?