Your husband sounds a lot like me. I had five tsx of IVIG and they did nothing for me.
Now on my second round of Plasmaphresis, plus remain on Prednisone, and Cellcept.
Pbresis gave me twenty very good days. Didn’t get to throw my walker away, however, I walked better, was stronger, and the brain fog lifted.
Hang in there and keep praying, all any of us can do.