i think that you plant needs to be watered because the pic shows a plant that is streching, the roots are growing right now and are searching for water, while, on the other end the leaves need light....about the watering schedule i think that if the medium drains too fast and does not hold any nutrients then you need to water often, propably you need to turn to your 2 waterings every day......
hydroponics is a grow in which you have to provide somehow a constant flow of nutrients so as the plant feeds constantly, the roots do not have to stress looking for food etc.....your friend would be right if the grow would take place into soil with some perlite mixed into it for better draining......
i am not an expert on this but i think i'm right.....