they should because the stepfather is the dad not the bio father
A birth father is a genetic father of a child, as opposed to an adoptive father or stepfather.
now a stepfather can't adopt a child without the concent of the child's father
If you're asking who the baby is to the one who gave birth to it, the baby is the child of the half sister, making her the baby's mother. As for the stepfather, he would be the child's father and step grandfather. But if he and the half sister's mother divorce, then he would no longer be the child's step grandfather. But he would, of course, still be the baby's father.
In general, no.
No, only the mother can. On the reverse, should the father be able to sue the stepfather for aiding the mother in alienation the child from the father?
Possibly
Approved by the court
No, that is simply silly
Get over it..the kid doesnt want you!
No unless he adopted the child no
Get a lawyer. You have a couple of ways to assert your parental rights.
not without a court case