Archie Again

For about a month now there has been at least one call a day asking about how the thermostat works.  No amount of explanation sticks.  It is a butt simple digital version with 2 numbers, the Set number and the Room's temperature.  There is Up and down Buttons for changing the target temperature in the Set, and a switch to go from Fan Auto to Fan On.  And of course the Heat/Off/Cool switch.

He doesn't understand the concept of the Set number.  It's getting hot out and hot in here so I should flip the switch to heat for hot, right?  How do I change the Room Temperature number manually?

Last fall he understood perfectly when getting himself ready for winter.  Half a year later that is all gone.

I can't even get him to leave well enough alone now that he AC is set up by my, and not worry about it until September.