IANAL, but I thought that the only time the lender owns the property in question is when the property serves as the collateral for the loan. This is standard for mortgages and car loans.
In other words, if you don't pay your car payment, the bank can repossess your car, because the car is the collateral for the loan.
For the typical price of a Powerbook, it is very possible that the loan in question is an unsecured loan. In that case, there is no collateral, and (depending on how they do this) either the money to buy the Powerbook, or the Powerbook itself, is a gift.
And if the loan doesn't get paid, the only thing that gets taken is his mom's credit rating. ;-)