For parents, that is a tough one. Light distros like AntiX,Vector,or Puppy take some getting used to for older users. You could have installed XFCE in AntiX for your parents using the Meta Package installer available in AntiX.
I guess you could look at SalineOS also for your parents. MacPup 529 is pretty easy to understand for older folks if you run the JWM windows manager instead of E17. JWM has that Windows 95 feel to it.
Like I said. With parents, (ha, I am a computer illiterate linux biker grandparent), recommending a distro can be a tough one if they are not as adventurous and set in their ways I guess.