I completely disagree. Talk about overkill! You'd be buying way too much computer and spending too much money for something which would be used just for Internet browsing.
OP, I'd go for a small, reasonably priced laptop over a tablet. It would be much easier for typing. No drinks near the keyboard would solve the spilling problem. If you do go for a tablet, you can get a keyboard to go with it.
I am a little surprised so many posters here think 60-70 years olds can't use computers!
Very good point! The OP is getting great advice from posters with their experience, I was coming from my mil, who is using her iPad for everything, even some banking, and she has gotten frustrated. And her dd moved in with her airbook and decided that would've maybe been a better choice

(her dd and dh and I have iPhones, and he set up her iPad to get iMessages - she woke up to 50 messages confused at the dinging - mind you we included her because her dd was at the ER needing stitches, MIL just couldn't figure out where the dinging was coming from! There were a bit of silliness with that, and she was glad we included her, she just couldn't believe she couldn't figure it out, which may be why she wants a laptop?
However, I didn't mention my mother had a laptop, did little but surf on it, and got jealous that a few of us kids/grandkids got iPads, so she demanded an iPad - and she uses it for games and surfing, Facebook etc - - and she loves it! My dad hates that she is always on "that thing"

Esp when they travel, because he always has to help her get online,
so as the OP is discovering, it all depends on what they need, how they will use it and how people around them have technology!