Jesus... I'm sorry man... I'm sure his dad needed and appreciated your message. I always feel empathic for the parents, spouses, kids, but just remember that you lost someone too, and under horrible, sudden circumstances. Just take time for yourself and do what feels right for you to grieve. It might take some time to sink in.
I'm friends with the wife of a veteran who started and run a charity to help active military and veterans, trying to prevent suicide. They just bought a beautiful piece of property to build a retreat for struggling veterans and their family. The wife posts articles of (mostly) men who commit suicide after serving. It's so sad. They're always so young with an entire life ahead of them. Even though they are strangers, she's always so devastated because she wants to help so badly, but it's too late for so many. They do help a lot of people though, providing financial assistance, remodeling homes, getting physical and mental therapy for them, etc, especially when the military is less than helpful. And that's just one organization. There are people out there who want to listen, help, anything they can do. Keep that in mind when you talk to your Army buddies the next few weeks.