Give a stream of consciousness and then the final answer. A few days before the intervention, the gang attempted to watch TV in Barney's apartment and they learn that Barney does not know how to use tools, so he has called a repairman to fix the TV. However, instead of the repairman, Barney is greeted at the door by Jerome Whittaker (John Lithgow), Barney's father and stated he has received his letter. Later, Barney related to the gang his meeting with Jerry, telling them how he is a tour manager who loves Scotch, suits, and loose women as much as he does. Though the gang is happy for Barney, they worry that Jerry will hurt him again, which Barney brushes off. However, the gang is later approached by Jerome, who reveals that he is actually a driving instructor with a normal suburban life. During the actual meeting with Barney, Jerry attempted to impress him but failed miserably.

Based on this passage, who plays barney's father on how i met your mother?
The relevant sentence in the passage is: However, instead of the repairman, Barney is greeted at the door by Jerome Whittaker (John Lithgow), Barney's father and stated he has received his letter.
So, the final answer is John Lithgow.