Can MassHealth take money from bank account?

Hello everyone, I am asking this question for my uncle and I am sorry if it does not belong in this section. He is 60 years old and is a disabled veteran with no income other than a monthly check he receives. From what I gather, when he went to withdraw some money it was rejected. When he called his bank there were no funds in there and they stated that MassHealth withdrew the all fund that were in there. He recently had knee surgery which is why I think they would take it but last week he also found out that he has lung cancer so he has been using his insurance. It is too late to call the state and I have never heard of a health insurance withdrawing money directly from someones bank account, any insight will be helpful. Thank you