Where do you live?
I'm not sure what (herbs,etc) is available to you locally...
If your Mom has ulcerative colitis, the causes include poor eating habits, stress, food allergies , also infectious agents , like bacteria. It's often associated with use of Antibiotics which alows the microorganisms that are normally held in check to proliferate. If you're seeing clear moving creatures in her bm, to me that would be an indication there are parasites present.
In order to be able to give her a course of anti parasitic herbs, you'd have to improve the condition of her colon, otherwise it will all be expelled too quckly (and may be too iritating).
Acidophilus, on empty stomach at least 2x daily. If dairy intolerance, try non dairy formula.
There is Aerobic Bulk Cleanse (ABC) from Aerobic Life Industries, containing healing herbs that cleanse the colon.
Alfalfa, in tablets or liquid is healing to the colon.
Since the bowel's condition is weak and point to infammation, try aloe vera gel (with irish moss, which makes it even more soothing).There are many herbs that are beneficial: chamomile, dandelion, feverfew, papaya, red clover, slippery elm, yarrow and pau d'arco.
Lobelia is good to drink. Also may be used as an enema for inflammation of the colon for a quick relief.
The medical community is trained mostly in the pharmaceutical treatment of illness and you'll not get anywhere with them if you point out symptoms they are not educated about. You may even get labeled as a wacko, as some people I know, who had parasite symptoms got sent to a shrink to get therapy for something they were told they must be imagining.
The diet also should be very soothing as in steamed veggies,everything soft, well cooked and non irritating.
I hope this helps you out.