There are a number of ways to reduce ER stress and I'm far from an expert, generally anti-oxidants do the trick, if you have a similar illness I'd look up studi

There are a number of ways to reduce ER stress and I'm far from an expert, generally anti-oxidants do the trick, if you have a similar illness I'd look up studies for your specific illness, they often do in-vitro tests of specific compounds to test their effect on diseased cells. In my case I try to avoid alcohol, and I supplement with high doses of rosemarinic acid extract.