I have one...she also has lymphangectasia. The meds helped her in the beginning when she was first diagnosed. She is on a home cooked diet that I got from a board certified vet nutritionist. There are RX foods that they do well on. I just opted to do home cooked.
There are a few YTers who have more experience than I do...my Cookie was just diagnosed in December 2011.
Hope Coco is feeling better soon!