Unfortunately, there are several plants that have this common name. Almost every multi colored plant is called Joseph's Coat by someone.... Croton, Coleus, Iresine, etc. One of the big problems with common names is inaccuracy.

Thanks, I will try to look up Joseph's Coat online and have her look to see which one it is that she is talking about. Thanks again for the info.

I think the one most commonly called 'Joseph's Coat' is Alternanthera ficoidea....I had it years ago, but don't have it now, unfortunately.

It is commonly grown outdoors in 'warmer' zones, but it does well as a houseplant if given good light (mine was in a south window).

Good luck finding your friend's desire!
If you don't have any luck here, try the 'Plant Trading' forum.