Hi Frizzini . I'm sorry about your father's condition.
I must admit that this is a very serious & complex condition.
There have been no large studies regarding IgG4 treatment.
Most of the data regarding any IgG4 studies, seems to be coming from Japan, with glucocorticoid treatment being the common treatment option.
However, in advanced stages of IgG4, when there's very significant organ/system involvement, it is questionable if any treatment using immunosuppressive agents, would make any sense, when a risk benefit analysis is done and the risk most likely would be much greater than any benefit.
Your email, for privacy reasons, cannot be displayed here, but I will send you some information in a pm.
My comments are not intended to replace medical advice.
Best wishes to you and your father.
Niko
I'm in a related way myself, and fibrosis seems to be std now. Has your father's issues made their way to his liver yet? Very likely will showup in the bile ducts. Our immune systems certainly can be nasty when gone amuck.