I tried to reread Jojolion to understand what Araki left behind when he finished it, but I was baffled by just more contradictions.
we know rock humans the only known source of the fruit sell it to very rich people like celebrities and athletes for 200 million yen
but we discover that Holly was experimenting on the Locacaca in a lab she created at T.G University Hospital. Her motive was to cure viruses and germs, However, she failed in her research because viruses are living organisms.
Tamaki Damo was very very careful about anyone stealing the fruit to research it, to the point they weight the tree after every transaction.
Kira and Josefumi manage to steal a branch, to grow a fruit and heal Holly's illness
Damo finds out
they were so meticulous they checked every ill person in japan until they got into Holly and her son kira, because no one would steal the fruit except to cure an illness
but they never knew about Holly having her own lab before coming into the hospital
Holly's disease was related to her brain, she started becoming forgetful
her CAT scans show parts of her internal organs and her brain missing with almost surgical precision, not turned into rocks
at first I thought this is a clue, that she was ill because of something other than the fruit, but..
in chapter 92 we find out the rock is moving across her body
this made me believe that maybe, to hide the experiments on her done by Doctor Wu, they managed to make the rock parts move, to not appear on the scans. but this was never stated outright.
the story ends with Holly remaining ill despite saving her being Josuke's whole motivation to chase the fruit