We were on the Millie Oct 14 - Venice to Barcelona. We had cabin 9102 (or was it 9201?) Anyway, it was mid-ship and CC and we were delighted. It was under the spa and we never heard anything after the 1st night when they were delivering luggage. We loved the overhang, as we could sit outside in all kinds of weather and we loved the perks - especially the CC Breakfast Menu and the comfortable bed with NO GAP between the beds.
You might want to look up the deck over Sky and see exactly what will be over your mom's cabin, but in October very few people were using the pool deck anyway.