Luvfraz, there is a known hereditary component to IBD. It isn't directly inherited, but people with a relative who has IBD are more likely to get it themselves. Current thinking is that UC is an autoimmune disease for which some people have an inborn predisposition, but it takes other, not fully understood, triggers to activate the disease.
Your son is lucky to have more choices than were available a decade ago, and there are new treatments being developed all the time. Hopefully he will find the solution that works for him, and soon be feeling better.
Moderate to severe left-sided UC diagnosed 2001.
Flared for 5 years, finally in remission with Remicade since March 2006.
Avascular necrosis in both shoulders is my "forever" gift from steroids.
Colazal, Remicade, Nature's Way Primadophilus Reuteri.
"My life is an ongoing medical adventure"