Are you on an antidepressant? I noticed that when I started Pristiq, my stress levels dropped and my symptoms improved... What about
triple antibiotic therapy? Have you asked your GI about
that? I saw an article about
Vedolizumab for UC. It's still in trials but it sounds like it has potential to treat difficult cases of UC.
https://www.healingwell.com/community/default.aspx?f=38&m=2431246
I am happy it sounds like you've at least gotten some control over your MIL ;)