Nah, I don't think that The Last December is particularly about JW. Or at least, different to other songs on the album, it can be interpreted however it fits you.

Last December


If ur Last December came what would u do?
Would anybody remember 2 remember u?
Did u stand tall?
Or did u fall?
Did u give ur all?

Did u ever find a reason y u had 2 die?
Or did u just plan on leaving without wondering y?
Was it everything it seemed?
Or did it feel like a dream?
Did u feel redeemed?

did u love somebody but got no love in return?
Did u understand the real meaning of love that it just is and never yearns?
When the truth arrives
Will u b lost on the other side?
Will u still b alive?

In the name of the Father
In the name of the Son
We need 2 come 2together
Come 2gether as one

In ur life did u just give a little
or did u give all that u had?
Were u just somewhere in the middle
Not 2 good, not 2 bad?

In the name of the Father
In the name of the Son
We need 2 come 2together
Come 2gether as one

The Rainbow Childen is as adventurous an album as Prince has made in the last 15 years for sure , but like others on here I agree it does impress less after repeated listenings . The music when its good is very good , and I'm more than happy that Prince is putting out gems like The Digital Garden ,The Work and Family Name ,its got some fun lyrics as well as the Jehovahs ramblings also (which I dont let bother me ) , it beats the shit out of Musicology for sure.
Its not a great album though , it'll just be remembered as proof that Prince never lost it and can throw his fans a curve-ball whenever he pleases.