I work on the genetics and genomics of Cryptococcus, and actually it can often be quite tricky to treat as common azoles (most likely what your dad was treated

I work on the genetics and genomics of Cryptococcus, and actually it can often be quite tricky to treat as common azoles (most likely what your dad was treated with) are often ineffective (they tend to be fungistatic instead of fungicidal). Had the azoles not worked they would likely have moved on to using Amphotericin B which is a pretty nasty drug, though much more effective on Crypto. Systemic fungal infection in general are pretty difficult to deal with because fungal cell biology and physiology is not all that dissimilar to ours (on the grand scale of things).