When Robert S. Letchinger asked his doctor for a prognosis a few months ago, she didn’t give him a clear answer.“I don’t have a crystal ball,” Letchinger’s wife Chris recalled the doctor saying at the visit.“So he went onto Amazon and bought her a crystal ball.”The gag didn’t end there. He put the crystal ball into a Godiva bag so that his oncologist would think it was chocolate.This classic humor brought a smile to everyone around Letchinger and was something he maintained …