Hi SoulfulYin and it's great to hear that your mum is doing as well as she is at the moment.

Hypersalivation can be caused by a number of conditions.

I wonder if one of her medications is the cause. Make sure she's drinking a good amount of water and not getting dehydrated if it's really bad.

Hopefully that resolves soon, but certainly worth talking to her doctor when she goes next.

I understand your worry about having something go wrong at night. It's not good for you to get caught up in the "what-ifs" although it's totally understandable and I do it myself!! take care there.