I have had immunoglobulin infusions every 4 weeks for some months, due to my CLL. Plan to be at the infusion center for several hours (that was very unexpected to me). To help alleviate side effects, they give you Tylenol and an infusion of Benadryl. The Benadryl can burn, so it should be infused very slowly. Once they start the IVIG, they also infuse that slowly. With me, they increased it at 30 minute intervals (hence it taking several hours totally). After several times, they were able to change the interval to 15 minutes. I fortunately had no side effects, other than bruising all over my arms (I am told I am a 'hard stick', so it generally takes several tries). Since I am on blood thinners for my AFib, my bruising takes a while to go away. Other side effects of IVIG can be headaches or nausea, but I don't know how common that is. Be sure to be well hydrated; they generally also give saline along with the immunoglobulin. I found this link that may give you more information: https://www.uptodate.com/contents/intravenous-immune-globulin-ivig-beyond-the-basics.
I don't know about funding. My guess is that each manufacturer of the product used may be able to help. Good luck! Go see that first grandbaby!