Wow! What a TOUGH decision.
I feel for you. I wouldn't want to be in your shoes. I know I could never not live without Jackson, I miss him sooo much when I have to leave him at my dads if I'm going somewhere, I literally miss him sleeping in the bed with me. I couldn't do more than a week or two without him (and even that is hard). Maybe that's me being selfish, but I just couldn't part ways. With you being so close, is there no way you can pick him up after work, and maybe just leave him at your moms during the day?
What I would personally do is probably enlist in doggie daycare, or a petsitter coming to my house once per day. A lot of dogs are often left home for 8 hours at a time, that's pretty common for working dog owners. So I don't think it's totally a terrible thing to do, but do think a dogwalker or daycare would be really beneficial (if, of course, he doesn't stay with your mom). If I was trying to make your decision, I would probably get a 2nd dog, to keep each other company. But I know that's not always possible with everybody, and not always the solution. It's just something I would do.
What are your hours that you're going to be away? Like an 8-5 type of deal? If so, I don't see an issue with getting home at 5-6pm, being able to still give Emmett a walk, or playtime, etc. Also, Jackson also lived his whole life at my moms house with their dog and she got hit by a car and died when Jackson was almost a 1year old, yeah he was really upset without her for a few weeks, but then he got used to being the only dog. Dogs usually adjust really easily, and alot faster than humans. You've also gotta think... what about when you're finished w/ grad school? Are you going to want to take him back... because that seems more unfair to me. By living even longer with your mom and dog playmate, the harder it's going to be to take him away from there when the time comes.
Whatever you decide, I really wish you luck. You will know what's right and what's best.
