New Owner, Humbly Looking for Guidance

It might be a good idea to get the title and maybe even have it signed over, that way there isn't any question of ownership.
The son has been told by his dad (my buddy) to sign my buddy's name to the title. I am supposed to receive the keys, the title and the car. I don't think the problem is the son. I think the problem is the D-I-L, and her vocal talent in swaying a reasonable man's mind. And is also why my buddy suggested to hold off calling his son until tomorrow (Friday), to coordinate picking the car up. That will limit the time available to the temptress / blabber-mouth.

The only reason the D-I-L has been tolerant of my buddy, and all the hassle and loss of privacy with him and his wife moving in, is she found out how much money he has (hence why he gave me the car). And since finding that out, she's been playing "cool" with him, hoping for a payout.