Natural persons A and B live as neighbors of detached houses. For years, B has ridden 75-year-old A on grocery shopping trips because A does not have his own car. Now A's daughter C gets to know that B handles A's banking and KELA (Social Insurance Institution of Finland) matters. While visiting A, C notices on the kitchen table a deed that A has sold his summer cottage property to B the day before. The purchase price is at least 50% below the current price, which makes C genuinely concerned about A's financial situation. C wonders how B can handle A's affairs at the bank and KELA, and whether the summer cottage trade between A and B is legal.

Take a stand on C's reflections: What legal action is involved when B handles A's affairs? What are the characteristics involved in this legal action? What is required for a summer cottage property transaction to be valid?