What are some good foods for someone undergoing kidney failure and with diabetes?

Control diabetes. First diabetes diet is very important. Then low salt to control BP and potential swelling. If kidney failure is not mild then animal protein and dairy product restriction is important. After dialysis starts then can push animal protein for better nutrition but not before dialysis. In other words, restriction is the main recommendation, no good food to recommend but good dietary regimen/restriction.
Avoid sweets. And reduce protein intake see nutritionist in order to 'do it right' and be able to comply.