Why can't Rheumatoid Arthritis be treated w/ Intraveneous Gamma Globulin?

Did your brother already tried using supplements like deer antler velvet from kinglyvelvet.com which is really helpful for people suffering from arthritis especially rheumatoid arthritis.It has an active ingredients such as IGF-1, chondroitin and glucosamine good for the bones and joints. My mom has been taking it since last year and I noticed that she was able to do the usual things she does unlike before. Hope this helps!