I have a 16 year old daughter. When she was age 2, her father signed over his parental rights so that my husband could adopt her. We allowed our daughter to have contact with her biological daughter through the years. He was recently in an accident where he later died. They are doing an investigation whether she is entilted to receive his workman's comp pay. Could she legally receive it?

If she was adopted, she has no legal claim to her biological father's benefits. It works both ways, as he had no legal rights to your daughter.

What if he wanted her to have legal claim. We kept him in her life? We all did this because it was in her best interest to be adopted by her step-dad.

It depends on the source of the payments. If they were governmental, then no. It it was insurance or any other assignable asset, then he could have willed them to anyone, including your daughter.