I have every sympathy for the lady, losing a son is a terrible thing to go through.
But I wonder if she sends letters of complaint criticising grammar and spelling to all her friends who sent condolence cards?
I do not agree with a lot of Gordon brown's policies, but the man is a human being, and a human being who is blind in one eye, has poor vision in the other, and admits he struggles with written correspondence. He takes the time to hand write letters when he could easily have had a computer bash out an impersonal reply.
This seems like an unnecessary attack on a man who was genuinely trying to express his sympathy, and is being used for nothing more than political warfare.