I guess my question is, can you focus the scope to your Uncorrected eye and bypass having to use glasses all together?
Within limits.
Image focus: If you have to change the focal lengths within the scope to adjust the image focus to your eyes, you will be introducing parallax.
Reticle focus: You can adjust for reticle focus. That is what that adjustment is for. It adjusts the diopter to your eye. However, if you have astigmatism, that can affect how the cross hairs appear, sometimes to the point you see two or more cross hairs! For that, you need special correction. Your grandfather almost certainly was just adjusting reticle focus, as most run of the mill hunting scopes have factory preset parallax. That does little to nothing for image focus.
Eyeglasses causing parallax? I don't think so. First of all, glasses are fixed on your face. Your face is not moving around behind your glasses like it does behind a scope, which is affixed to your rifle. Secondly, if the image coming through your scope is parallax-free, it should not matter if the image is "bent" by your glasses. The reticle will still appear in the same place in relation to the image. What you see is what you get.
Same thing about having the optical center of your eye glass in line with the optical center of the scope while sighting. Shooting while wearing glasses with a normal optical center will not throw your shot off, the image just won't be as clear as it could be, and there may some astigmatism coming through as well. If your prescription is mild, you'd do fine with a normal set of glasses without having to worry about where the optical center is ground.
I searched and searched and drove all the local optometrists crazy until I finally settled with Safilo Team Elasta 4146 frames as they look nice, aren't made in China, and come in a narrow bridge. You want a high, inside corner as square as possible, and as close to your nose as possible. That's where the narrow bridge comes in. This frame is best for narrow faces.
JMO