Bava Batra 135: Deathbed Gifts, Believing the Word of One's Brother

What if a childless man states on his deathbed that his wife will not be a yevama nor will she participate in yibum.  Instead, she is fit for a Kohen Gadol.  The rabbis clarify how this could be possible.  Is he believed if he says that he divorced his wife, and thus he simply meant that she would not do chalitzah nor yibum.  Of course we know that a kohen gadol is only to marry a virgin.  Can he be believed about the future if we do not believe him regarding the past?  Rava suggests that we require his wife to perform chalitzah to be stringent.

But what if a man were to claim that he does not have brothers on his deathbed when people overseas say that he does have brothers?  Rabbi Chanina taught that a woman is believed if she tells a beit din that she was captured but not raped, or defiled.  In such a case would she be forbidden to her husband because people overseas know that she was in fact raped?  Abaye affirms that we are lenient about a captured woman's word.  This is because she makes herself repulsive to her captors. But should people become lenient and allow women to marry when perhaps they should perform chalitza?   The rabbis are conflicted.

The Mishna taught that a man is not believed if he says that another man is his brother.  The Gemara walks through what should be done if the other brothers admit the relationship or if they deny it. The rabbis also consider the distribution of property if one brother should die, and the possibility that the value of the property changes quickly.

A new Mishna teaches that if a brother dies with documents tied to his thigh regarding gifts to be given after one's death, they should be ignored.  If the brother states that he wishes to give whatever is written in the note to someone, it is permitted even if that line of inheritance is not accepted.  A healthy person's gift, however, might say: from today and after I die.  The rabbis are unclear about whether or not something can be a gift if it says "from now".  The rabbis continue to argue about whether or not we believe and follow the instructions that accompany a gift.   Are there conditions on the acceptance of such a gift?  For example, if a person states that the gift is intended to help the other person, is that enough to justify its acceptance?