Please find out of you have foster parent classes available. We took them when we got our grand kids. They were so informative.
I caution you to not let him call you mama until you have adopted him. At any time the biological mother or father could come back, be clean and sober and have a job/home and there be no legal reason he can't live with them. It's only been 2 months and it could go on for years but all in all, you are not his parent and the court can't keep a child from a parent who isn't currently doing anything wrong.
Custody/guardianship is temporary. Adoption is permanent IF both parents are on board and sign the adoption papers. Mom could sign and say dad didn't want to come but then he can come back later and say he never knew or understood that was what was happening and demand his child be returned.
Either one could ask the court to place the child with a closer relative too.
They will take him out of your home and put him back with them. This will be heart wrenching for you and for him if he's identified you as mom.
You can tell him that his mom and dad love him and they're working to do better. You need to protect your heart and remember that he's not your child. Then at some time if he is available to be adopted you will be there for him and he can call you mom.