I'm sorry you're going through this. It really depends on the therapist. My T hasn't been sick that long but when she has been she has always stayed in contact with me. She works in private practice so this may be different compared to a T who is employed by an agency and sees clients there. My former T was off for a short time with an illness and it was the agency who contacted me, I didn't have any direct contact with her despite some text contact during normal times.

I was going to say the same as Rive above, maybe speak to her about this on her return and agree on a plan going forward about staying in contact during her bouts of illness if she agrees.