I think my bro gave it way some kind it fish oil in the water and this happend idk why tf he did it will it come back ? Should I count cut off all the dry stuff??
If they did it may have coated the roots and its suffocating the plant.
About the only advice I can give is to flush the pot thoroughly and then renute and add back some microbes, then leave it alone and seee what happens
Looks like it may be outdoors ...so make sure its in the shade all day.
Raise the light slow the grow let it recover.