I am so sorry that you have so many other health issues to deal with and so, so sorry for the loss of Mom and your home. I have heard that stress can be a trigger for a relapse and you have had major stress! My dad died last year and it is so difficult to lose a parent. I'll pray for you.
In answer to your question, I don't seem to have a problem with lights but more with sounds. It seems that I have supersonic hearing now and some sounds drive me crazy. My balance is almost back to normal, but I still can't walk for long distances. I still get very tired sometimes and although my speech is back to normal, I still search for the right words sometimes. I've noticed that my memory isn't what it used to be and I have to right a lot of notes so I don't forget to do things. I've also noticed slight problems with fine motor skills like picking up small objects and I drop things a lot, but other than that I'm doing pretty well.
Because HE is very rare, they don't really know what causes it. I have a family history of thyroiditis but no one has gotten encephalopathy. The hardest thing to come to terms with is that this is a relapsing condition, however some people have a complete remission and go on to live a normal life. The way I look at it is that I have this condition, but thankfully it is treatable, and although I'm not and never will be the same as I was before, I can and will lead a productive, "new" normal life. I try to take each day at a time with the knowledge that if and when I relapse, I will be able to get through it. When I first got sick my sister found a wonderful website from a woman named Beverly Seminara, who has HE. Her information proved invaluable to me. I've posted the link below. Thanks for replying and have faith. I've found out that I'm much stronger than I thought I was and it's true what they say "What does not kill us makes us stronger". Have a good night.