Helping my neighbors with an AC problem

My next door neighbors are a really sweet retired couple. I’ve never asked their ages, how rude that would be, but I would guess both of them to be 70, maybe even 75 years old. We get along very well, and the lady will even bring me a slice of pie whenever she bakes one. Her apple pies are literally the best I’ve ever had. All this virus talk has me worried — not for myself because I am still young and healthy — but for my neighbors, who are very much at risk! I haven’t seen them in a few days due to self isolation, but last night they called and told me their air conditioner was not working and they didn’t know what to do. I understood their problem, due to their shaky health they were scared to call an HVAC tech and let him into their home. They were in full-on self quarantine mode, well stocked with food and water, but they really needed their HVAC system to be working as well. I called around for them, to see if anyone could at least come over to inspect the outside components of the HVAC system, but I couldn’t even find that! I took a look myself but since I know nothing about air conditioners that was no help. Finally over the phone I asked her to try taking the batteries out of the thermostat and replacing them. What do you know, that little problem was all there was to fix, and once the thermostat lit up again they went back to happy isolation.

a/c worker