Waldenström macroglobulinemia (WM): Anyone on zanubrutinib (Brukinsa)?

My dad has had this diagnosis for years. He is 86 years old. He Was treated with “infusions” forever…idk the name of med. Recently however..a new oncologist prescribed zanubrutinib…2pills twice per day. I believe the highest dose but I could be wrong.
After 1.5 weeks my dad couldn’t tolerate the side effects any longer. He lost his appetite, a significant amount of weight, he had Chills, and extreme fatigue.
Doc has since taken my dad off the meds and will see him next week.
Soooo…..does anyone have any experience with a similar situation? Thank you in advance
Am I crazy to request he go back on the infusions?