There was another letter on the forum recently that was fake. (Has anyone got a link to that?) The strange thing was it said nothing terribly outrageous either. I don't know what the motive was.
In this case the motive may be to slightly exaggerate Watchtower eagerness to ask for donations. But not exaggerate too much as to be unbelievable.
It did occur to me the style may be slightly different because it is from a local branch in Africa. But I think some of the layout and textual features are also inaccurate.
I think the letter is fake.