The theory is that with some (if not all) UC suffers the good bacteria in the colon has been compromised and is pretty much non-existent. As a result the bad bacteria has taken over and causing the symptoms of UC.
Many people take probiotics orally trying to repopulate the colon with good bacteria. This works to a certain extent in some people but the gut flora is made up of hundreds of different bacteria strains which you can’t get from probiotics.
Fecal transplant is taking the stool of a health donor (after the donor has been screened), mixing it with saline solution and transferring to the sick person as an enema. If you’ve never heard of it before you are probably grossed out right now but this treatment has been used by doctors to treat people with c diff infection and has a 80+% success rate with c diff. There is no real data with it being used for UC.
If you search “fecal transplant” at the top of this page you will find a lot of information and discussion about it or just google it. There is a doctor in Australia, Dr Borody, who is the pioneer for this treatment and does it for UC also. He also has a protocol for doing it at home.
Unfortunately I have not come across a medical doctor who will do FT for UC and definitely not with kids.
I don’t know how open your daughter’s doctor is to this kind of treatment but maybe you could ask.
I wish your daughter the best of luck with whatever treatment you decide.