Bava Batra 114: Cancelling a Deathbed Gift; Mothers Inheriting from Sons?

The rabbis are discussing visiting a person who is sick.  We are permitted to make decisions about inheritance when we are on our deathbeds.  Today the rabbis ask about a person who makes a gift on his deathbed but does not die immediately.  Until when can that person change his/her mind and cancel the gift?  Perhaps it is alright to cancel one's gift as long as the parties are seated.  Perhaps until the discussion ends.  

Three people are permitted to write down or execute one's wishes in a deathbed experience.  But why is this the case if the dying person can retract his/her statement of inheritance?  The three people can only take action once the conversation has changed and/or once the visitors have left.

A new Mishna teaches that a woman can bequeath to her son but cannot inherit from him.  Why do we teach this, the Gemara asks?  Didn't we learn already that a son inherits from his mother but does not bequeath to her?  The answer is that we learn from this Mishna that a mother bequeaths to her son just like she bequeaths to her husband.  And just like a husband does not inherit from his wife after his death  - because her wealth goes to her family rather than his - a son does not inherit from his mother after his death when that money would be bequeathed to his paternal brothers.

At the end of our daf, we learn that both fathers and mothers inherit from their sons.  This statement might suggest that the tribes of the mother and of the father are seen as equal.  It is not only the father's tribe that is gifted the property of a son.  The mother's tribe matters as well.

To lose one's child is horrendous.  It would be critical to understand the rules of inheritance before the death of a child - whether or not this is an adult child - to avoid any arguments at that unthinkable time.