My mom is pretty adept with her iPad. If she was instructed to download an app, load it, and then stand in the kitchen after doing the button-push on the microwave, it would be completely within her ability. She knows what a wifi network is, she knows the password for hers. She is definitely slowing down a bit with age, but she rarely requires me to come over and help her with such things, at most she just asks for more confirmation these days before she says yes to a prompt.
That last part could also be because I harp on it every time the topic comes up, that under no circumstances should she be answering yes or ok to any random prompts that she isn't very familiar with already, and please call me if she's at all questioning the legitimacy of what she sees.
If it has a companion app for a phone (which this appears to be), you could easily have the phone do this for you. Not unlike setting up a wifi hotspot.
Just have support walk them through a menu on their phone for an "advanced" feature they just tap on, then hold the button on the microwave. Voila!
(Granted, I did tech support long enough to know this isn't easy; if someone can follow instructions, however, it should be doable.)
That last part could also be because I harp on it every time the topic comes up, that under no circumstances should she be answering yes or ok to any random prompts that she isn't very familiar with already, and please call me if she's at all questioning the legitimacy of what she sees.