The changes that Brooke Astor made to her will giving her son a greater share of her fortune reflected the clearheaded love of a mother, not a failing mental state that allowed her to be easily exploited, a lawyer for her son said in his closing argument on Tuesday. The defense pointed to testimony by Mrs. Astor’s butler, who said he heard her tell her son to take a $2 million commission on the sale of her beloved Childe Hassam painting, "Up the Avenue," a work she had formerly promised to the Metropolitan Museum of Art.