Don't forget that Vistana does accept deedbacks. St John has high maintenance fees and Sheraton Vistana Resort has no resale value. On the other hand, if your weeks come with Star Options, you should check if they are transferable to your brother. If so, it maybe actually quite valuable to your brother. There are no fees to trade within the Vistana system, and also no exchange fees in II.
My SVR 2BR LO comes with 95,700 Star Options with maintenance fees of only $1500, which is a real bargain. It is much lower than Sheraton Vistana Villages. No Vistana/MVC Club trade fees and no trade fees in II and it has Vistana and Marriott II exchange priorities.