Sentence 1: There was a grandpa who was behind the times. 
 Sentence 3: He bought him a new smartphone 
 Sentence 4:  The smartphone was too advanced for the grandpa 
 Sentence 5:  The kid was happy to try to help his gramps though 
 Option 1: His grandson wanted him to stay behind the times. 
 Option 2: His grandson wanted him to be up to date.