Where in their posting do they indicate they have cancer?
I don't know, however,
In his March 12th posting with some reasons why he can't work on the game but promising to,
it says
"When my sickness was already recovering, it turned to the worse at one point. I was suspected to have cancer. Two years ago, my aunt died due to cancer, and last year my grandpa was diagnosed with late-stage cancer. Thankfully, after more tests, the doctor came to the conclusion it was a baling tumor that got infected for whatever reason. He wasn't able to say for sure, so he sent me to another doctor that was specialized in the exact field. I managed to confirm this diagnosis a few days ago."
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So maybe the dev has it, or maybe it was presumed from the above posting??
who knows....
edit:
Also, there have been a few posts with promises of working on the game and reasons why
they can't as well as promises to keep in touch but those were a few months ago.