Hey, great to see you!!
A lot of cats don't care for prescription food or the like, so that's normal, if very frustrating. I've been lucky so far, so I don't have any suggestions of my own, sorry. I know none of my cats like the Light stuff, it must taste *blah*. I wonder maybe you can find a similar food to the SD Light? Don't know how many products you have available to you, but maybe there's another kind of Light food that might work instead.
Haha, Dad may be weak, but that's ok, I think it's good there's an alternative food until Taby decides to try the Light stuff. No harm done.