simple large button remotes on Amazon
https://www.amazon.com/s/?ie=UTF8&keywords=elderly+tv+remote&tag=googhydr-20&index=aps&hvadid=54537540636&hvpos=1t1&hvexid=&hvnetw=g&hvrand=14040473944834296578&hvpone=&hvptwo=&hvqmt=b&hvdev=t&ref=pd_sl_8u1g4krtf1_b
Make sure they can turn the tv and cable off and on.
Writing out instructions - really doesn't help. They are not going to follow it.
My experience with my family members who are over 80; most didn't finish high school. None went to college. They haven't read an instruction book or manual (ever) . They find them difficult to follow. They loose reasoning skills. They loose reading comprehension skills.
I have caught my mother more than once off to buy a new TV cause her's "broke". She repeatly says the remote is broke, the TV is broke, the Cable is bad. When she has once again messed up the remote.
I took nail polish and marked on/off button red. Channel changing green and volume blue. Sort of helps.
I know with my mom she doesn't want to try to learn. One mistake and it is I can't do it. She doesn't have the ability to reason through a problem.
I work in a store that gets a lot of elderly women. Some have their iPhone 6 out and they are sending texts and photos, playing games.
Some never did start in with technology and can not get the hang of even a simple remote.