The eye's experience of DOF varies for two and only reasons when looking through a Keplerian telescope. The first reason is a change in the focal ratio of your eye's optics, not the telescope's. Your eye is the part of the optical train that is analogous to a camera lens and the eye's focal ratio is determined either by the diameter of its pupil or the diameter of the exit pupil of the telescope, if that is smaller than the eye's pupil so that it imposes an artificially small aperture on the eye.
The second reason is a change in the telescope's magnification so that the size of the circles of confusion observed in the image enlarge with increased magnification and shrink with decreased magnification. In this case there is no actual change in the amount of true defocus at different magnifications (as expressed in the number of diffraction rings), but an impression of greater defocus and decreased DOF is created when diffraction discs consisting of the same number of diffraction rings increase in size with increasing magnification.
In short, your eye will experience the same DOF through your telescope as through any other with the same magnification as long as the effective pupil opening of your eye remains the same.
There are a few things that can create an illusion of differences in DOF where there are none; like focus speed, field curvature and high aberrations. I would suggest looking at those.
