This is a hard question. Vacation and rest time is important to everyone. And being in the US, I don't think enough workers get enough of it. On the other hand, the very nature of the therapist-client relationship is different than almost any other "helping" profession. I personally could not be with a therapist who takes off extended time as with the OP. With my relational injuries I need more consistency than that provides. But, as long as that therapist is open with that expectation, I don't think there's anything "wrong" with it.

For me personally, I think 4-5 weeks off, broken into 1-2 weeks at a time, is where I would be comfortable for "vacation time." And that's with the understanding that I would probably still feel slightly abandoned, but I know that's my own baggage!