I'm looking for what the title says. This is based on the book by Edward Griffins. Is laetrile actually fatal because of its cyanide content? Or can it really help in this fight?
Yes, there are several articles describing experimental data from animals and clinical trials in humans. The results clearly show that laetrile is not effective for cancer treatment, and the drive for laetrile as a cancer drug is widely considered to be a quack. See for example this NCI summary or this article.
Laetrile is a modified form of Amygdalin, a toxic plant product found in some seeds and nuts, for example bitter almonds. The compound contains a cyanide moiety and can cause cyanide poisoning. It was labeled "Vitamin B17" by Ernst Krebs in an attempt to get the compound classified as a nutritional supplement rather than a pharmaceutial (to escape FDA regulations), but this is misleading; it is not a vitamin.