....the greater mystery it is why they would start my son on 60 mg....

Probably because that's the size of the "normal" pill.....

I think I read somewhere that only 600 people per year are diagnosed with MG - most hospital staff don't know that much about it, and most of them don't know the symptoms of a Mestinon overdosage.

Since he was in an emergency situation, there wasn't time for them to experiment with fine-tuning; since he had a stomach bug, they probably attributed his nausea to that rather than the Mestinon.

Now you will have time to figure out what dosage works best for him, and get it on his medical records.

I'm so glad that you are having a positive experience - it makes all the difference in the world!