An old lady decides to check on his 3 son-in-laws

She wanted to see who respects/cares for her the most. She goes to the lake near the eldest son-in-laws place and jumps. The son-in-law dives in and rescues her. Next day, he sees a toyota corolla parked in front of his house with a letter -- Thanks from your Mother-in-law.

Then she goes to her second son-in-law places and jumps in a lake near his house. The second son-in-law also saves her. Next day he too gets a toyota corolla as a gift with a letter -- Thanks from your Mother-in-law

Now the old lady goes to her third son-in-law's place and jumps in the lake. He does not save her and she drowns. Next day he sees a Ferrari parked in front of his house with a letter -- Thanks from your Father-in-law.

edit: An old lady decides to check on HER 3 son-in-laws