Thanks RR! Two brothers and a sister watch over my mother who is in a small "care center." She is well tended and happy there. She told me she misses her home (and I'm sure she does), but in her condition she cannot possibly be left alone. She does not want to come West to live and my siblings are not home to watch over her. I admire what you are doing for your parents. When we lived in Phoenix, we had a zone alarm that alerted when the patio door to the swimming pool was opened. Something like that may be the answer you seek!
Mr. RR has already contacted the "zone alarm" people. He was a bit upset (to put it mildly) when he found I spent two hours in a blizzard looking for Dad. It all came out well in the end....no harm, no foul. But Dad and I are still in the doghouse. French toast, sausage and snuggles should solve that problem in the morning. LOL!!
Life without adventure and chance is no life at all. IMHO.