The circumstances NEVER warrent killing an innocent person. If you want to put the rapist to death and liquidate his assets, so be it. But you cannot make innocent individuals who also did not consent to being put into this situation the victim.
Using your logic, were a newborn child to be orphaned through an automobile accident, the child's next of kin could leave him to starve on the street because they "did not consent to take on that responsibility in the first place."
The solution is to make childbirth safer. If you are talking about the burden of raising a child, that burden does not exist as there are hundreds of thousands of couples - here in the US - that will take a child even if they have severe medical defects.