you could take different types of real leaves.. wash them..dry them.. then take melted chocolate of orange ... yellow... red... green... paint with brush and blend these colors on leaves.. let dry... peel leaf from back of chocolate.. then make some acorns from chocolate clay.. get you an acorn and go by that if you don,t have the mold.. this would be very pretty on the chocolate cake... hth
what was going on in the year he was born? could you find a paper from the date, or mock one up, and get an edible image? or how about just piles of chocolate, truffles, moulds, mini bars of things he likes? even something like if you pipe it into squares, and put a little chocolate - i dont know if americans have/ call them maltesers, minstrels - in the middle, or some m&ms or smarties.
You also could do something like a favorite hat or shirt of his and make it into a cake. He had to be involved in something during his life that could give you a stepping off point. Like was he in the Navy? Or what kind of job did he retire from? Incorporate something like that into it!
I got this sexy man (plastic doll), wearing a bottom red bikini, laying in his side, like at the beach, and I will make a regualr design on the cake, on top there goes the man, and a message like" 91 years of magnificense... or 91 and looking great!! At that age, humor is everything!!!