It is vitally important that your loved one's TV ad Cable STB (if any are correctly set up so that when they turn on, they g to the right input / content source, for example, the Cable Box or Antenna.
The settings are mostly in the TVs, and are now called "Power," "Display," "Home Screen" or older devices, "Input / Source" Settings. A few very new Cable STBs based on Google or Android operating system also have them.
Some STBs now also have a Home Screen or go to a Home Screen or Guide.
Please see the links below for information on these other devices. You may also need to contact the TV manufacturer or Cable provider for more detailed information.
Google TV - same for all brands - see also Dish Hooper
Vizio - set to antenna or WatchFree+
Dish Hopper - Scroll to "Power Settings"
Cogeco Epico - see also Dish Hopper
All Others, like Insignia, Toshiba, etc:
Use your TV branded remote then look in the settings, then follow the onscreen prompts to set your Input / Source / Power On selection as appropriate (different brands may use their own terminology).
You may need to refer to your manufacturers manual, or google your TV brand, followed by something like "home screen power on settings"