I got an offer. Can I email POI/department mentioning my SO's application?

[ConstantPresence]

SO applied to a different program and the school is both our top choice. A few acceptances and rejections from his department are already out and he didn't hear anything so far. We want  to do whatever we can right now to increase his chance of acceptance. Will emailing either his or my department (or my POI) help in anyway? Will it hurt?

[aco2]

54 minutes ago, ConstantPresence said:

SO applied to a different program and the school is both our top choice. A few acceptances and rejections from his department are already out and he didn't hear anything so far. We want  to do whatever we can right now to increase his chance of acceptance. Will emailing either his or my department (or my POI) help in anyway? Will it hurt?

I cannot imagine that emailing anyone in your department will make a lick of difference in either direction. If acceptances and rejections from his department are already going out it seems quite likely that their decisions have largely been made and they are now in the notification stage. You may just have to wait it out. 

[Yas-man]

I don't think it would hurt but I'm not sure it would help either.

[GeorgiaTechPhd]

Contrary to what everyone else has said, I think it can make a lot of difference in your application, if they know that one of you have already been selected for this school.
However, it also depends on whether you had mentioned this in your application beforehand? (Yes, many people apply together to same schools, and explicitly mention it in their applications. Most schools tend to be very considerate about such things as they value the mental and emotional health of their students, and often try to accommodate both students if they are particularly interested in one of them)

Another thing that matters is whether you have applied for PhD or Masters. Whatever I said above holds more for PhD programs than masters programs, since PhD is a longer and more difficult commitment. 

Still, I would suggest that you should talk to your PI -- explain your situation to them, let them know how important it is for you, and ask if there is anything that can be done. Out of all the people, your PI would care most about your personal wellbeing and will honestly let you know what your options are.