Yes, he was highly inbred, but claims that 80% ( or even 29 out of 30! ) of white tiger cubs die from inbreeding are entirely fallacious.
"Sara Iverson has produced a genealogy showing the two white tiger bloodlines converging in America, with Mohan and Begum on one side and Como Zoo's brother-sister pair of wild caught Amur tigers on the other. Iverson's chart illustrates the critical junctures where the bloodlines intersect, first with Kesari and Tony at Cincinnati Zoo and later Ranjit and Obie in Omaha, like marriages between royal houses. According to "Tigers Of The World", the Indian subspecies was, at one time, represented in North America by five individuals, all siblings highly inbred for white coloration with co-efficients of 0.406. All of this means white tigers have been greatly inbred.
It is not true that infant mortality in white tigers is 80%. This urban legend seems to have originated with opponents of white tigers. Poor husbandry, stressed mothers and feline infectious enteritis (for which a vaccine is now available) played a large part in white tiger cub mortality.
White tigers show a problem called inbreeding depression - continued inbreeding to fix a particular trait (the white colour) shows up other deleterious genes in the population. As a result, white tigers are prone to being cross-eyed and have other problems as noted later. Andy Goldfarb, tiger trainer who worked at MarineWorld in Vallejo, has said that when stressed or confused all white tigers cross their eyes. Inbreeding depression can be overcome by crossing white tigers to unrelated orange tigers; although the offspring will all be orange, they can be bred back to the white parent to produce white cubs. White tigers are now found in numerous zoos, not so much for conservation purposes (since they are essentially "man-made" and most are mongrels of Bengal and Amur tigers), but because they are a hit with the public."