My Father was diagnosed with MG two months ago and began taking Mestinon?

This link may be helpful. It also contains a link to a support group. Good luck.
See: https://www.drugs.com/health-guide/myasthenia-gravis.html

I am very sorry that your Father has been diagnosed with Myasthenia Gravis.
This disease is horrible on a younger person, and I can't imagine how your Father must feel. How does his Dr know that he hasn't had the symptons of the MG for awhile and it had gotten so bad that his Dr just recently had him tested for it? I have never heard of anyone his age having this attack thier body suddenly. When I was diagnosed with MG in Nov. 2003, I had symptons for a month before I decided to see my PCP, he told me that I was weak due to recent surgery, Then I had double vision and my right eye was drooping and I saw my eye Dr, A blood test was done on my eye, to check for MG. It was Positive and I was referred to a Neurologist. I had several more tests done, and was put on Cellcept and Mestion and what a miracle drug Cellcept is. I've been taking it for 8 years and with no side effects. I would like to add, that after having symptons for a month or more, I did have MG strike me suddenly as I was working on my computer. I thought I was having a stroke. Sharp pain hit me in the right side of my temple, and right eye. My right eye drooped and had pain in it. My hands were weak and I couldn't lift my right hand to my face to apply makeup, or do my hair as it would just fall back down. I had no control over my hands. My legs were so weak they felt like I was walking on jelly and I was extremely tired 24/7. After the eye Dr diagnosed me and not my PCP and the Neurologist saw me and I started the Cellcept, along with Mestion I started doing much better. I did have about a 6 wk period where I had double vision for the second time. What a bummer this was. Not being able to drive was very depressing.
I will say a prayer for your Father, and hope is will feel better soon.