Mom won’t return our puppy :/

Hi, any help or guidance here would be greatly appreciated i am honestly a wreck. For context - We have a 5 month old pug puppy. We live in Ontario, but our families are in Nova Scotia. We both had the whole month of Dec off, so instead of flying home as we usually do, we drove so that we’d have the car there over the month at home (grandma was in hospital so thought it might be helpful to add another set of wheels, anyways I’m rambling). Brought our puppy home with us, had the best month. Flash forward to the end of Dec, we’re getting ready to drive back to Ontario because we have to move from Kingston to Toronto by January 1. After really mulling it over, many conversations, we decide to leave our puppy back with my mom until the second week of Jan. That way, we could get the move done without risking him being uncomfortable and avoid putting him through another long drive. He loves flying, just falls asleep, but long driving as we discovered on the way here isn’t his favourite. Obviously had we taken him it would’ve been fine and we would’ve cared for him excellently, it was just one of those situations where if you have the family support willing to dog-sit, probably wise to take them up on it. As more key context, my mom has always been very positive about us getting a dog (we are 22, live together in a very nice spacious apartment and both have full time jobs after graduating university). She always praised us as great puppy owners. Well, til now. Today, we flew home to pick him up and my mom has never been more distant. She is clearly distraught, and i understand that she probably got attached to him, but she is being so cold to me and keeps making passive aggressive comments about how big of a commitment having a dog is (as we well know) and how much travelling we do (which isn’t true…we never travel). I wish she’d just communicate her concerns to me, or just admit that she’s sulking because she’ll miss him so much, but she’s being passive aggressive and I’m questioning how to solve this. She is obviously implying he should live there with her. For example, she keeps making comments about how bonded on to our family dog he is, how happy he is there, etc. Not once have we ever questioned our fitness as pet owners, we love him more than anything and one of us works remote full time so our puppy is literally never alone and gets the most attention ever. Until now, she’s never showed concern about him and actually the opposite, had been nothing but positive. I have this pit in my stomach about the thought of flying away with him now… this sounds crazy but it’s as if now he feels like a chess piece and my mom is playing some weird psychological game. Please help!!!!!