which medicine i need to give for Bernard? I can find it.
After Bernard gets sick you need to go home and do some studying. You'll learn about the Spectral Syrup, but it needs another ingredient, the Heat Ocasia, which you can only find vague references for. You can try to figure it out from those vague descriptions, or you can go chat with the Lizardfolk priestess Othra. She can tell you how to make it (if you've met them and are on speaking terms with them).