14 year old hates me now

I coach girls basketball of the high school my son goes to. Last week my son said he needed to talk to me and he said I can't tell anyone what I'm about to tell him. I said okay. He told me one of his friends is being abused by his dad. I asked "Like his dad hits him?" And he told me "All of the above is what he told me. Hits him. Screams at him. Touches him." I told my son that I have to report that. I'm a mandated reporter and I can lose my job and go to jail if I don't report that. He started begging me not to because he promised his friend he wouldn't tell anyone. I said if I don't report he may not have a friend for much longer. Because how much longer until his dad goes to far and kills him or he takes his own life. So I had to call. My son is angry at me because his friend was removed from his home and sent my son a text saying he hates him and he broke his trust and to never talk to him again. My son is angry with me and said he wished he never told me. I feel bad but at the same time I legally have to report stuff like that. I don't know how to make it up to him or get him to understand.