If you’re two days in you’re fine. Wouldn’t be my first choice but I have no idea why someone would think that it’s dangerous. Most people don’t know anything about fasting and those of us that do it and study it still misunderstand things all the time.
What was their reasoning? Any sources? If my family said something like that, I would just brush it off since none of them fasts nor have done any research about it.
If you’re drinking water you should be fine, alcohol does dehydrate you which is my water with electrolytes help out a lot but there’s nothing you should be worried about, especially since you say you’re fine.