Different types of UC and Bleeding

Mild inflammation (the lowest grade of UC inflammation) can cause blood on tp after a poop, drips of blood in toilet water, and blood on stool. The severity of inflammation determines how much blood you see, the more severe the more there is. Extent is really hard to gage, not entirely impossible. Best you can tell is based on where the craps or pains are (left side, across belly button, and/or right side). But trapped gas can cause those sensations as well, so there's a bit of ambiguity.

I hope your boyfriend's flare is short and mild.

Yes, bright red blood is rectum and it gets progressively darker the further up it is. It gets red, and then dark wine red within the large intestine. Small intestine and higher stomach bleeding eventually gets a black color.