Hello,
Absolutely!
Besides being the Mother of a bride that was in the same situation, I am also a retired US Army Colonel that served in the medical corps in Desert Shield to Desert Storm.
My daughter was married in July 2006. My grandson aged 6 was the best man, my grandaughter age one was the flower girl. They had a lovely wedding at the MGM Grand in Las Vegas with a reception to follow at The Venetian Hotel. My daughter opted for a traditional, formal evening wedding and family flew in from all the US and England. No one judged the circumstances at all, nor thought it in bad taste. It was a celebration of love with family and friends.
Under the circumstances of your son-in-law having served his country, their marriage and the birth of their child, they certainly deserve a combination wedding, anniversary and welcome home party.
Let me know if you have further questions or concerns.