Hello and welcome - I'm sorry that you and your wife are going through this. Graves' absolutely does put a strain on family relationships.
Stabilizing thyroid hormone levels can make a huge difference in terms of emotional swings – so hopefully, your wife is keeping up with regular doctor’s visits and with her daily regimen of taking medication.
Other than that, one suggestion would be to talk to your wife directly to see how you can best support her. Some patients *want* their family members to be closely involved with their treatment plan, while others would prefer to *not* have to discuss their Graves'!
Family counseling might also be helpful if your wife is willing to pursue this.
Some of the GDATF's videos will hopefully be helpful to you; I especially suggest “The Emotional Aspects of Graves' Disease” by Dr. Ira Lesser.https://www.youtube.com/user/GravesAndThyroid/videos
Wishing you both all the best!