HELP tank water is green!!!!!

Short story short our tank water turned cloudy one weekend about a month ago. It was definitely NOT due to overfeeding. My dad did a water change and put fungal medicine in because our oscar had some fungus on it's eye. This turned the water GREEN. Fast forward a month the water is still cloudy and is greenish. my dad did water changes everyweek, checked the filters, put water clearer in, and the water wont clear up and it is still green. He is Pissed about it and says next weekend we are putting all the cichlids in a bucket and draining the tank and clearing it all out and refilling the tank. I am telling him this will kill the fish but he is more concerned about water and says that we have to do it. I have a female Jaguar cichlid and an Oscar... What do I do?!?!

Well.... As much as I told him no he is going ahead and doing it right now... He says he is just doing a 90% change.... Really love my fish but looks like i might lose them not to happy right now