It's also called cutting next years fruit buds off. I would leave it as is, and hope you get a few fruit next year. Citrus should not be pruned back in this manner.

Your father should have left the tree alone. Dooryard citrus need not be pruned at all. Exceptions: aesthetic purposes, to remove cold-damaged limbs, and to rejuvenate OLD TREES with reduced vigor. - Millet

I agree you should never prune citrus this way.
If it's not to late already, please hurry and paint the trunk white with ordinary (cheep is good) latex house paint. it will protect the bark from sunburn.