If a kayak overturns, it is much easier to get out if a person is not wearing a life jacket, you just slip down out of the seat and up you go to the surface. When wearing a life jacket, it's more difficult because you have to go down to get out of the seat, and that's tricky when the life jacket is pushing you up. It is also possible to right an overturned kayak by using the paddles without leaving the seat. It just takes a bit of practice.
So it seems to me, more and more unlikely that she got into trouble in her kayak.
Unless she was drugged, she should have been able to save herself.