Hi delta3. Sheldon died a while ago and as far as I know he was over 80 and still in remission from colitis.
I was diagnosed about nearly ten years ago myself and tried his diet and method but it didn't really help me that much, but the diet can gradually reduce symptoms. I've tried a lot over the years and done a lot of research into drug free methods and have achieved lasting remission for several years now.
What I would recommend you do, and what I would do now myself if I was just diagnosed, is to get a juicer and make juice from carrots, apples, kale or collards and Celery and drink nothing but these until you have no more bleeding. It may take only around a week. It takes a lot longer usually to get results by sheldons diet.
I think the juice is the quickest way to see results but you can add some solid foods like cooked veg and rice if you can't manage that.
I also recommend you get your blood tested for vitamin D status and then take enough D3 daily to get it over 60 ng/ml and also take chelated magnesium and ideally Epsom Salts baths to raise your magnesium levels which will help the D work.
There are a lot of things you can try dietwise and Sheldons diet was a big part of his success. I think maybe his age helped because people sometimes find it easier to get into remission at his age possible due to less active immune system. That's just my theory though
But really I think you need to correct immune response by optimising vitamin D levels and controlling diet at the same time. It may take some time to raise your levels if you are low and there are some good websites that have advice on how to do this. The vitamin D council's site is a good one
The juice fast allows your bowel to heal rapidly and you can then follow a suitable diet free from refined and inflammatory foods. I recommend you get a masticating juicer as these make better quality juice.
Please don't resort to drugs as they will make it harder for you to truly heal your digestive system.