Yeast infection of the colon

My husband is hospitalized with ulcerative colitis.  Prior to coming down with diarrhea symptoms, he had sores in his mouth which were recently diagnosed as thrush.  The ulcers in his mouth look the same as the ulcers in the colonoscopy photos on his colon.  Could this be a yeast infection in his colon?  

[springyes]

I don't think it would be a yeast infection, I too have ulcerative colitis or did until I had my colon removed back in 2001.  I had ulcers in my mouth also and very red eyes that I think were all associated with the colitis.  They were like flat red dots everywhere and all over my tongue.  My tongue was very dehydrated looking which made it look like yeast but it was from being so dehydrated.  When you use the bathroom that many times in a day it doesn't take long before you become dehydrated. How long has he had colitis?