As a Hindu myself - my 2c on the topic... Hinduism has no central doctrine, so while this particular priest may hold a view on organ donation (or lack thereof)

As a Hindu myself - my 2c on the topic... Hinduism has no central doctrine, so while this particular priest may hold a view on organ donation (or lack thereof), there will be others who may encourage it. As an example - Lord Ganesha's head is "donated" from an elephant. The concept of organ reuse isn't new. There just wasn't the technology to deal with it in the past. I may not be as learned as the priest you know. But I have yet to find any of the priests I know tell me organ donation goes against any scripture.