Have you seen your GP? If not, that would be your first port of call. A lot of things can cause blood in your stools and honestly, once you start paying attention, it's very easy to  start noticing other symptoms. Things like harder or softer, larger or smaller, stools happen and will be more noticeable if you are already concerned and with both anxiety and blood in your stool, you are bound to be paying extra attention.

That said, while the cause could well be something very minor, like hemorrhoids or a fissure, there are more serious things that can cause those symptoms like polyps, Crohn's or cancer so the sooner you get an answer, the better. If it's a minor issue, you can stop worrying and if it's a serious one, the sooner it's found, the sooner it's treated.

I think your cousin's situation would be relatively uncommon even with cancer. Plenty of people are treated successfully