Yes, and I agree with greene that we'd need to see pictures. But even that might not tell us a lot about which citrus it is. Unless it's a grapefruit, which tend to have larger leaves with a lobe at the stem end, most citrus look very much alike.
He may have to wait until it produces a fruit to know.
Your Calamondin is a much better type of citrus for growing in a container. It will stay smaller its whole life. The biggest Calamondin tree I've seen here is about 12ft. tall and 8ft wide. Very beautiful and productive.