I am going to retrace my searches and gather the links and post them.

The antibodies for AAG and AGID is referred to as Ganglionic AChR antibodies and sometimes neuronal AChR antibodies. They have similar symptoms despite the name.

Here is a pretty detail article on AAG.

http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2677210/.

Let me know how your brother makes out.
kathie