Hi-
I first had symptoms of UC when I was about
60 years old. You're probably right about
aggravating the disease if she was eating high (insoluable) fiber foods. I did that, too.
One thing to realize is that when you have numerous bloody bowel movements, the food is not being properly digested and you're probably going to become anemic (which causes weakness).
It is important to introduce probiotics (friendly flora) into your digestive system to process the food better and slow things down. I am now 70, no longer have bloody BMs but take an ultra potency multivitamin with iron daily to combat anemia.
There are a number of websites containing some good info about
natural treatments that can help your mother to feel better. cureforulcerativecolitis.com is one.
You don't mention her taking anything by mouth. Many doctors in the US believe in "treating from both ends" and prescribe something like Colazal (balsalazide generic) by mouth and another mesalamine in enema form. Steriod foam enemas are also commonly used but the doctor might suggest a mesalamine enema which may be easier to get.
I hope this information provides a basis for discussion with the doctor. You might print out some info from a UC-related website to help out your GP.
My best to your mother and father. Keep in touch....