Army won’t let undocumented immigrants attend graduation

My friend who is Mexican recently joined the army. During basic training she’s been writing me letters, in one of the letters she told me that while their drill Sargent was explaining graduation and told them that if their parents, friends, or relatives were undocumented they couldn’t go. Their Sargent said that in the past they have deported someone’s parents attending their sons graduation for being illegal. So my friend will only have her father attending her graduation since none of her family have papers and can go smh. I do not know much about the army but i have never heard of this until now and i think it’s straight up wrong. This is a very big moment in anyone’s life but you can’t share it with your loved ones because they will get deported if they show up?