I'm very sorry to hear about your Dad. It's very possible that your Dad's passing has been a very traumatic experience for the dog too (they grieve just as we do). Their behavior can be an indication of their emotions. I think this is something that can be worked through and is hardly a reason to "put a dog to sleep". Give her lots of love and attention. Continue to praise her for going potty in the right place, just as you would a puppy. I pray everything works out for everyone. Please explain to your Mom that putting the dog down is not an option just because she's having a difficult time lately.
: My mother has a 12 year old spayed female who has always been very alpha and on the snippy side, but over the past six (plus) months her aggression has escalated. She has also (in the same period) begun soiling the house, and I'm concerned that she's developing cognitive dysfunction -- I should also add that my Dad passed away within this same period, so there may be a stress related issue too.
: I'd appreciate any/all input -- my Mom is getting close to deciding to put the dog to sleep because of it.