I think your only option is to find another therapist. Let's be honest: your therapist is never going to cut back on her vacation because you or some other client complain. She is past retirement age as you say and I don't think it's realistic to expect her to suddenly decide to take less holidays just because you asked her. On the other hand, you clearly need a therapist who is more available, which is perfectly fine. I think it's pointless to talk to her because like I said, the situation remains the same: you want her to be more available that she is willing to be. Personally, I don't think 1 month and a half of vacation in a 6-month time period is unreasonable. It's actually the amount of vacation most therapists in my country take. But since you need someone more available, this therapist no longer seems like a good fit.