It's good to hear that M seems to be improving. Have they told you what the illness is? Covid? Something else? Or is that part of the stuff that they don't feel like clients need to know or worry about. And I guess they still can't tell you an estimated return date?

Given all that, I'd say, what's the harm in trying? Keep your "boundaries", your guard up. Talk about generalities of coping with life, the pandemic, not too deep on how M's absence is affecting you. Try to use your observation and intuition to get a some kind of a gauge, may be wrong but a start anyway, on what she is really like and what she might be able to provide in terms of "support". If the first session doesn't go well, then no need to make another, is there?.