The biggest obstacle to a grandparent using IPTV comfortably on their own is usually not the remote itself, it is the number of apps and inputs they have to switch between to get there. Reducing that number of steps matters more than finding a simpler-looking remote control.
Fewer steps beats a simpler remote
If reaching the IPTV app requires switching the TV input, then opening a launcher, then finding the right app icon among a dozen others, that sequence alone is enough to stop daily use, regardless of how intuitive the remote is once you arrive. Setting the IPTV app as the default launch screen, or placing its icon first in the row, removes most of that friction in one change.
Choosing the right device in the first place
A device with one remote and one interface is consistently easier than a setup involving a separate streaming box remote plus a TV remote plus a soundbar remote. See smart TV versus streaming box for IPTV and the best devices for IPTV for which setups minimise the number of remotes a household needs to manage.
A favourites list matters here too
The same principle that helps children navigate IPTV independently helps grandparents just as much: a short list of the channels they actually watch, set as favourites, removes the need to scroll through a long guide to find a familiar program. Write the channel numbers or names on a sticky note near the remote as a backup during the first few weeks.
What to test before leaving them to it
Before considering the setup finished, have them turn the TV on cold, with no help, and reach a favourite channel unassisted. If they get stuck, that exact point is the thing to simplify next, whether that means a labelled remote button, a reordered home screen, or a shorter path through fewer apps.