Satre is using the word hell to mean "the afterlife" i.e. we live on in other people's minds and opinions whether we like it or not.
Also people don't have to be dysfunctional for it to be a form of torture, we are trapped in their minds (gaze?) no matter what.
I think you may have been distracted by the semantics over the ideas. I'm talking about hellish people, not hellish relations. Hell is other people. People who are hellish. How I'm using hellish is correct.
> we live on in other people's minds and opinions whether we like it or not.
I don't think Sartre really cared if we lived on in others minds at all. The issue is that the way in which our own minds were affected by 'the others' gaze.
The hellish part to Sarte is the affect other have on our own psyche.
> Also people don't have to be dysfunctional for it to be a form of torture
According to Sarte's clarification it looks like that was his intention, however, I still agree with you, just the presence of the other can be hell.
From Sartre: "I mean that if relations with someone else are twisted, vitiated, then that other person can only be hell."-Sartre