M.S.
I am very interested in your question. While I have not been in your shoes, I will be in a matter of months. When my husband returns from his deployment we will have a brand new baby at home, and our son will be 19 months old. All of our family lives in the same town, so sometimes it is hard to escape from them. I want our family to come first, and allow my husband to connect/reconnect with our kids without having to fight for his attention among everyone else and I don't think it is too much to ask.
The only advice I have right now is to let everyone see him outside the house. Go out for dinner, go visiting etc. That way once he has had a few minutes to visit, you can decided it's time to go home and you don't have to wait for people to leave your house. Or, as someone else suggested, dedicate a day to celebrate the graduation. Let people come and go all day to see your daughter and your husband, and once the day is over you can let everyone know you guys want to be by yourself for a few days.
Like I said, I haven't been there. Good luck and let me know how it turns out. Thank you, and your thank you to your husband. His service is greatly appreciated by so many of us.