My father has 100% blockage of an artery. Will chelation therapy work?

No. I feel that chelation is medically useless and a great way to lighten your wallet! blocked arteries are caused by atherosclerotic plaque. The cause of the plaque should be treated. See www.Vascularweb.Org or www.Padcoalition.Org for more information.
No. Chelation therapy and blocked arteries is complete sham. Not a single study shows benefit. May be dangerous and definitely costly with no known benefit.
No, Bloodflow Needed. Chelation therapy is known to remove heavy metals {lead, mercury, aluminum...Etc} from the body. For many years it has been used off-label in heart patients. There is only 1 large trial that showed some benefit...The tact nih study tact nih study: http://www.Nhlbi.Nih.Gov/news/press-releases/supplement/questions-and-answers-the-nih-trial-of-edta-chelation-therapy-for-coronary-heart-disease.Html.
No . This is a complete waste of time your money. See a board certified vascular surgeon and ask if anything even needs to be done. Sometimes an occluded artery does not need to be treated if there is enough collateral circulation.