Hello. I am sorry to hear that so many problems are happening with your family. Since I have autoimmune illness in addition to mental health problems, I tend to look at trying to fix the medical problems first.
I am assuming that you mean that your wife may have
temporal arteritis. This is an autoimmune illness and really should be treated, if she does indeed have it.
Autoimmune illnesses can affect moods enormously. I would suggest that you concentrate first on supporting your wife in getting treatment for her medical illness. Once she gets that firmly diagnosed and is being treated for it, psych medication and/or counseling may be needed.
I wish you well and hope you'll continue to post here. This forum is a good outlet for feelings that we often can't share with people we know in our day-to-day lives.