The bowl is really not suitable for 3 goldfish. Does it have to be goldfish? I assume it needs to be coldwater so what about leopardfish or white cloud minnows instead?
Goldfish are very messy and, as said, would not do well without a filter or daily water changes.
If the boss is set on goldfish and doesn't care about their welfare so much, get the fancy ones that just hang about with droopy tails, not comets.
Is the 80 - 100L when it is filled to the top? Ideally it should just be filled to the widest part to give maximum surface area.