der Brucer - What you said to the young man was, IMHO, excellent. It allows him to understand that his parents love him -- and yet are misguided (to say the least). It's too easy - and at this stage not helpful - to paint the parents as vile and hateful. What he doesn't need right now is to believe that his parents, of all people, don't love him.
As for how to approach the parents - here's one thought for a beginning at least. Maybe you could gather a list of good films (and there are some, including movies for television) about parents coming to an acceptance of their gay offspring. (The trick is to find a few that do not deal with the gay character dying of AIDS!) He could simply ask them to sit with him and watch a film. I would think there is nothing threatening in that. Then talk afterwards about what they've just watched - not about them, but the movie. At least it might open up conversation.
BTW - I was reading about a book: BEYOND ACCEPTANCE: PARENTS OF LESBIANS AND GAYS TALK ABOUT THEIR EXPERIENCES by Carolyn Welch Griffin, Marian Jenks Wirth, Arthur G. Wirth - Sounds like it might be helpful.
Here's a brief review: "Every happy family is alike, and every unhappy family is unhappy in its own way," wrote Leo Tolstoy. Families dealing with a child's homosexuality are certainly forced by a homophobic culture to experience a whole range of unhappiness. Beyond Acceptance deals with a variety of issues facing heterosexual parents of gay children, from facing what the neighbors will say to worrying about AIDS and social ostracism to feeling angry and guilt-ridden.
Various people speak about how they came to their misinformed views about gayness, their religious beliefs, their fears that friends will abandon them after finding out about their child's homosexuality, and their anxieties about AIDS. Often people find similar solutions to their problems, and sometimes different ones, but in all cases the message is that understanding, love, and a need to own up to, and dispense with, ignorant homophobic attitudes can bring families back together in a wholesome and nurturing manner. Frank, informed, and filled with insights and practical suggestions, Beyond Acceptance is a fine addition to the literature on homophobia and families.