Aiming4 Goldfish Care

Ok my bff has had a goldfish for about 4 years now. once the bowl dropped and ripped his eye out, but he survived. But his life is subjected to no plants, no gravel, just a plain pint of water. How do i tell her that its wrong without insulting her?

I just brought a very small 5 pint goldfish bowl for one goldfish.My parents keep saying it will be ok without any pump or filter. Is that true or is there a mini filter i can get for the bowl?