I tried to pick the "One of Us" option and he do said that he knows about the bloodstone and said that I have two option to find it, to a natural caves or a ruined research facility scattered everywhere in the island. Idk about any research facility but anyway, after mentioning the quest I tried to see the trading option but no bloodstone for sale. Only weak healing powder, mortal and pestle, weak energy powder, basic electric parts, and speed potion.
I think it's because the first time I tried to mention the quest I didn't try to look for the trading option and just went of somewhere so now it's not selling me anymore or maybe its something else entirely, my memory is not my strongest point.