Hi Sean, welcome to YT. My family and my inlaws are medium sized to large dog lovers but they really love Zoe and think she's just a cutie pie. Your mom will feel the same
I think also letting her know that you will not be leaving her to take care of the new puppy will make her feel better, too.
I'm so sorry you had to leave him behind, I'm sure you found him a great place to stay.
Keep us updated on your path to finding a new best friend