Tara,
Welcome to the forum.
Sounds like your son has been on quite a roller-coaster ride; I am so sorry.
It's good he is finally in a stable place, and is doing better.
I can't tell you whether to take or not take the meds your doctor is putting him on.
However, I would suggest you take some steps so that when he gets off the meds, he will stay stable. IMO, the way to do that would be to look into adding certain supplements like adding slippery elm powder and l-glutamine, probiotics, making some dietary changes, and looking into LDN, low dose naltrexone.
BTW, did he have his blood serum levels of vitamin d3 and b12 checked as well?
I was able to control my UC into remission through various supplements, probiotics, diet modification, and LDN , low dose naltrexone.
For more info on the protocol which has put me into remission, please go to this link: https://www.healingwell.com/community/default.aspx?f=38&m=1666318 , and look at the 11th post.
I hope you feel better and let us know how we can help you.