I too would recommend the Metamucil it helps to bulk the stool and absorb the liquid in the colon. I will have looser stools if I dont take it. I take it every night before bed, this way if it is going to cause gas at least your in bed. Start small and gradually increase the dose.
One med that helps for the diahrea is Lomotil it slows down the colon, helps with cramping, urgency and offers some relief so that he could enjoy doing things with his kids. It is a lifesaver for me especially when I'm flaring.
What kind of probiotic is he taking and how many live bacteria are in each dose? Every probiotic is different some are more powerful than others and every one has different strains of bacteria in them, make sure that the one that he is taking the kind of bacteria in it are beneficial to the colon and diahrea.
As for the fevers Tylenol should only be used, Ibupropen will make your UC worse and cause bleeding.
You mentioned steriods cannot be tolerated. Is that just oral steroids because the steroid enemas are different and are very beneficial they go right to the inflammation. Less side effects. I refuse to take oral steroids but I have great success with the enemas and so do many of us here. THey do more than any of the oral meds that I take. Hycort, cortenema, (cortisone enemas) & Rowasa, Salofalk (mesalamine enemas). Cortifoam is good for day use.
Exhaustion is a problem for many of us, you just need to sleep when you can and rest is very important.