Linux has been a great platform for the elderly for years.
My mother, who also is in her 80s, bought a Toshiba Latitude in 2007. It came with Vista and not enough RAM to run anything other than Solitaire. I installed Ubuntu, which took about 15 minutes, and fixed the sound config, which took about two days, and she's been fine ever since.
But her version of Ubuntu is no longer supported, and rather than try to upgrade -- she lives 12 hours away, so it's not exactly convenient -- we bought her a self-updating Chromebook on Black Friday. So far, so good, although she's going to have to switch to an HTML5 solitaire game instead of AisleRiot, which has been her go-to for the last seven years.
I'm still running Ubuntu on my own laptop, but Cinnamon may lure me away. I need to upgrade, and I am not a fan of what Ubuntu has done to the UI.