David are your parents on DSL, Cable or Fiber internet?
Do other devices in this room lose Internet connectivity during this time?
Do the streaming devices give an error saying they have lost the WiFi connection, or do they just not stream?
It sounds like interference caused by something on a timer, or perhaps some parental controls are set on the router. As it is just affecting that room, I would unplug everything but the TV and streaming device to see if it is something inside that room. Outside of that irrigation systems, pool pumps and lighting are generally the items outside the home that may run on a timer. Let us know about the above and we will try to help figure this out for you.