Motherly Love<br>Bob's mother was very nasty and never made him feel loved. In adulthood, he had a hard time trusting women. He finally married Kate but was unsure about having children. When she became pregnant, Bob worried about making a child happy. When he saw Kate hold the baby, radiating love, his fears dissolved.
Kate's mother in law was Bob's mother.
Bob married Kate, so Bob's mother is Kate's mother in law.  This question is tricky because it refers to people in the text in different ways than they are written about in the text. 
( z1 have-rel-role :ARG0 ( z2 person :ARG0-of ( z3 have-rel-role :ARG1 ( z4 person :name ( z5 name :op "Kate" ) ) :ARG2 ( z6 mother-in-law ) ) ) :ARG1 ( z7 person :name ( z8 name :op "Bob" ) ) :ARG2 ( z9 mother ) )