My son finally opened up to me about what happened in the military

This an update on my 19 year old... He was medically discharged from the army because he was having panic attacks and wetting his bed.. He had some serious PTSD and my husband and daughter made it worse. My daughter was being a bully and mocking him for getting kicked out and my husband sees him as a disappointment. Since we both moved out for his own mental health they've been posting on Facebook and my husband saying how he's proud of our daughter and she would never let him down like his son... Just disgusting. My son couldn't sleep last night and opened up to me about what happened... He said he met a guy named John at basic. John was the guy in the pictures. My daughter went through my son's stuff and found a box with love letters and pictures of this guy kissing him. When I asked about him he said it didn't matter because he's dead now. He said John some how snuck got a hold of orange sherbet ice cream which was my son's favorite and gave it to him. After that they became best friends which slowly turned into more. He said some others thought it was gross and we're homophobic but they didn't care. Him and John continued to write and when they got stationed at the same base it was magical. He said they had a 2 year relationship. And that he didn't tell us because he knew his sister would call him slurs and stuff. He said A few months before he died John asked my son to marry him and he agreed. When I asked how he died he only said grenade and then started to cry saying he saw him die. It broke him but it didn't stop there. Not even a week after he died he was in the shower and some fellow soldiers came to harass him saying too bad about your boyfriend and started getting handsy and he was held down by 7 and was assaulted in the shower .... I wanted to cry... He told me hel bled for weeks. He said he felt dirty and heart broken and he just snapped mentally... I cried and we hugged. He said he didn't even tell his therapist yet because he's so ashamed and I said he has nothing to be ashamed about. I feel like part of this is my fault for letting him enlist at only 17... I just hope my baby can heal