In my opinion - the trip of a lifetime for your mother would be a short flight journey, but stay at a lovely resort, place, or touring a countryside etc..

My aunt who's 80+ refuses to go anywhere that has a flight time of longer than 3 hours no matter (as she says) even if it has a living room (she's dramatic). At their age, I understand that it is difficult eg mobility , claustrophobia etc. She honestly says that she is quite happy (and she was) to just sit and read a book and watch the sunrise/sunset at a lake somewhere...

So perhaps you'd like to ask your mother as to what she'd like - instead of assuming that she would instantly like to fly in Suites on a long flight because that is something you would like.