For Clint, Roger's now-grown son, his dad really was that genius, but he's spent most of his life unsure if that genius was in tracking, and finding, Bigfoot, or just convincing the world he had. Roger is long dead, and he went to his grave swearing that the footage was real, but he had a very real financial reason to do so; for Clint, even doubting that the footage might not be real is enough for his mother to disown him from the family.