Now that I reread my own post, I realize I don't even fully agree with Cullen that "normally, it's not OK to hide gay." Maybe not in an ideal world, but this world is still far from ideal, and whether to be out or not should be a personal decision for each individual, not up for judgment by others. Even if the world were ideal and everybody was completely OK with every sexual orientation, it would still be up to you to decide what you want to say about your own.
Apparently David had his reasons for not coming out to his family himself years ago. However reluctant or frustrating his decision may have been, it's not his friend's place to override his choice when he's no longer around to make it.