My mother in law will accidentally disconnect her hose from her oxygen generator. Are there any devices what will alert when that happens?

I can understand if the cannula falls out of her nose; that's not unusual. But the only time I've seen the cannula become disconnected from either a stationary or portable concentrator is if the cannula isn't properly secured onto its "plug".

Sometimes it has to be twisted back and forth a bit to ensure that it's secure, but once it's on, it rarely comes off without force. In fact, in my experience, it's usually a bit difficult to remove.

Check to see if it's just sitting on the plug or if it's actually been twisted on and "screwed onto" the plug.

I would call the company that provides the oxygen equipment and ask them for suggestions. All of those techs have hidden talents to work through different difficult scenarios.