Buy a refurb Mac from Apple. I've bought several over the years and have never, ever had a problem. Safari will do everything they want. get them a gmail account.

My mom will be 93 next month. She emails all of us (her six kids and all of her grandchildren and the great-grandchild. All the cousins. And her far-flung friends.)

If a nonagenarian can do it, anybody can.