The way I understand it- if you sue and win money for medical expenses- both future and past then if someone else had already paid for medical expenses (past) that were incurred then they are rightfully owed part of the money to reimburse themselves.
As always- since Wal-Mart is big- they are portrayed as the evil doer- however morality is not based on being big or little. It sounds like the trust is trying to keep money that is not theirs- and if that is true then that is immoral and wrong- no matter who is owed the money.
Sounds like her lawyers didn't ask for enough in the settlement. They should have known about the WalMart policy.