My husband would like to adobt my son who is 4 he has been the only father my son knows his real father knows about him just chooses not to see or have anything to do with him we live in indinanapolis Indiana

Then start getting things together and have your husband adot the child. If the bio father wants nothing to do with the child then Im sure he will help in the process.

... If the bio father wants nothing to do with the child then Im sure he will help in the process.

Especially if he realizes that once the adoption is final he will no longer have to pay child support.

He is paying CS, isn't he, Rwanda69?

I would not recommend trying for an adoption without an attorney. So your first step should be hire an attorney. Then follow the attorney's advice on what to do.