If you want this to last a long time, quilting would be preferable to tying. When tied quilts are washed repeatedly, they can rip around the ties
I say go for it and quilt the thing.... it's a beautiful quilt, and wouldn't it be cool for him to look at it in 25 years and say, "my sister made this for me when I was in Iraq." It could last a century, and be passed down.
Just my 2 cents