“My son has two last names (ex. will-stre) I want to know what legal steps can I take to have the stre removed. There is no child support action against the father, but he is also not helping with child expenses on his own.”
If that is the name on the birth certificate, you will need to file a Petition for a change of name on behalf of your son. As part of that Petition, you will have to give notice to the other parent of what you are trying to do.