They should be supportive, here in the UK they are actually required to by law, but that doesn't mean in practice that happens. But some are, I 'came out' at work with my manager a few months back and they have given me time to attend appointments, conselling and even a support group weekly.

I do think more people being open about mental health is better for us all in the long run, we should not treat such things as needing to be swept under the carpet.