I would ask, and have done so.

I noticed a few weeks ago that my T had a bunch of pillows piled up against the back of her chair, and was being very cautious about sitting. I asked if she was okay and she said that it was an old back/hip injury flaring up. We didn't spend any time on it, but I know it would have bothered me if I didn't ask.

My pdoc had a traumatic brain injury last summer and was out for several months. When he came back, he had a note posted at the reception area letting clients know that he's doing well and didn't want to spend appointment times talking about his health. So, I didn't mention it, except at the end to say that he is looking well and hope he continues to improve. And I say pretty much the same thing at the end of each appointment with him, since I only see him every 3 months.