If that's what the reading said that means your friend already KNEW it on an sub-conscious level. (According to my understanding of Tarot.) There may have been some way to talk to him and bring up those s/c feelings/thoughts. Even if you had taken the direct approach, nothing says that he would have headed or even been able to head the warning. I had a looming Tower in my readings for awhile in 2001. It was warning me about my job. I knew it. I still could not/did not avoid the explosion.
I don't remember all the details, but one of my readings has always stuck with me. I used to read for a group of Readers online. The readings were free. But if the client wanted to contact us for future readings, that was fine too. One of the clients who fell to me was wanting to make a big change. The details wane, but it had to do with her desire to relocate, give up her husband/children, etc. something like that. I could immediately see from the reading that she was a bully. And I could see that her real problem wasn't this outside issue, but one deep in her soul. I did a number of readings and follow up correspondence for her, all gratis. I tired to steer her to seeing something besides running away ... but she was stubborn (just as the cards told me) and persisted in her chosen folly.
That reading DID teach me to be more aware of those tiny windows through which most people view themselves. They themselves are the only ones who can enlarge that window. If advice from a Tarot reader doesn't/can't do it, Universe will take care of it nonetheless.