@yellowdoggirl - What a frightening end for your friend!
I do know that anyone with diagnosis of either chronic sinusitis or chronic headaches should have imaging of the brain. CT is used for sinus diagnosis. MRI for persistent headaches.
Here again is a case where one has to advocate for oneself- or have someone else do it. It should not be this way!
I have medical knowledge, but I often get tired of arguing for tests or other treatment. It’s exhausting, especially when you always feel sick.