Bava Batra 136: What Can an Heir Do with an Early Bequest?

A new mishnah! On how a healthy person can transfer property to others -- to go into effect after that person's death: the phrasing of "from now until after death." But what happens to that property during the lifetime? Neither father nor son can sell those properties during the father's lifetime. And if the son did sell, the buyer does not have the right until father's death. But does the father need to say, " from now" to begin with? The Gemara suggests that the date alone should be enough. Also, the case of all of the above, but where the son dies in his father's lifetime -- what happens if the son has sold the property before he died? Does the sale take effect (say, after the father's death? Or not at all? It's a dispute between R. Yochanan and Resh Lakish.