Jenny,
Perhaps you could check on the status of
AMY-101 in Australia. It's a newer drug that shows promise for PNH treatment.
Do his doctors suggest ways to treat his low platelets and low white count?
Are you able to talk to his doctors? Perhaps your brother would allow you to talk to them directly, or accompany him to appointments, if you show him that you have a good understanding of AA and PNH and want to be supportive.