Do we know what Hana is sick with?
It is never revealed outright but it is implied to be AIDS. We know that Hana used to have a boyfriend named Ken who died (and caused Hana to drift away from the drag queen club). When asked if Ken died of AIDS, Hana glibly replies "No, he slipped on the soap". So the implication is that Ken did die of AIDS and probably passed it on to Hana.