this means : My son said that I did some stupid things and I never did even half of them i.e. I hardly did anything that my son claims that I did

it means that the son add extra things when he was talking about his dad. for example the father said that he would like to take a day and relax. and maybe the son says that the father said that he would like to quit his job and explore the world. "half the crap" this means that a lot of what the son was saying was not true and, that not even half of it is true. This is more of a saying than a literal expression.