Overnight scares

My father in law who my wife and I live with is super paranoid about his diabetes checks it about 12 times a day and most times a few times at night, since his brother died young from it. Hes 73 now and had it since 28.

Lately hes been really good but about once a month he will have his blood sugar get dangerously low overnight and wake up delusional until we give him some juice and calm him down.

Is there anything like a overnight Alarm that is reliable or something like this being developed. I worry one day one of us wont get woken up by him whens he's having an episode.

Thanks!