Not really. He'll pay support until the child is 18 and maybe beyond regardless. If he retains his rights as father he may have some say over how money is spent on the child which would in turn affect his support obligations.
If your friend relinquishes his parental rights in favor of someone else (i.e., if he allows the child to be adopted by someone else), then he has no further obligation to pay child support.. THis has to be a formal and judicially adoption. You should speak with an adoption attorney.
Relinquishing parental rights to another adoptive parent is an extreme course of action which requires court approval and is best acheived with the services of an adoption attorney. See a list of adoption attorneys in CA from the Academy of Adoption Attorneys web site. Once the rights are relinquished, there is no child support obligation. Also there are no longer any rights to see the child.
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