Bava Batra 154: Sick-bed Giving (Or: Not Every Ill Person Is on His Deathbed)

What happens when it's not clear whether a person was indeed on his deathbed? In the aftermath of determining whether his gift was valid, it becomes a matter of dispute - hinging on whether the rule of the burden of proof being on the one making a claim applies in this case. Plus, what happens when witnesses and a certification document contradict, and the person himself undermines his initial claim? Also, more on the dispute - specifically, the opinions of Rabbi Yochanan and Resh Lakish of the value of witnesses vs. a documentation, and why each is right in his position -- with interesting wrinkle, like whether one might have been a minor, and why we don't exhume the body to check.