Crazy Step Daughter What The Hell to do With her?

My ex husband got killed in Iraq 4 years ago and only had life insurance which he left 20% to his daughter from his first marriage and according to his well it say to pay the child support till his daughter is 18 and her expenses from tutor and buy her presents on birthdays Christmas etc. He didn’t have any contact with his ex wife 2 years prior to his death since she moves around a lot from state to state. So she sends an email every time she changes her address which is 2 times a month to send the child support so I been doing that. Now his daughter is 18 years old and showed up on my door and just like her mom, dropped out school and has no job and all she cares about is money so she asked the rest of her money and the lawyer gave her which is 3K and the lawyer gave it to her and she is pissed. Can she sue me since there was lawyer handling everything?