Better for who?
Cochlear implant surgery is still surgery. There is a risk of infection, including meningitis (the meningitis vaccine does NOT prevent all types of meningitis!) as with any surgery, there is the risk of anesthesia death, and really all sorts of complications to be considered.
Is it worth it in this context for the child to hear? Does the family (in this case, the father) value hearing? Do they consider it an acceptable risk that the child may be harmed or (rarely) killed by the surgery? Does the child have a condition that can probably be treated with surgery?
Does the child have any other medical conditions? Certain tests, especially an MRI, may be difficult with a CI and that is a consideration if the child has other medical conditions. It is also important to consider other medical conditions when thinking about how safe the surgery will be for the child.
Can they afford the surgery? Can they afford subsequent speech therapy? Do they understand the risks and benefits of speech therapy, and the long-term commitment required which may interfere with the child's ability to go out and enjoy their childhood?
Do they understand the risks and benefits of a deaf signing classroom versus an oral-only or mixed classroom? do they think they want the child to be mainstreamed? Will a cochlear implant help them accomplish their current educational goals?
Personally, I don't believe it is ever ethical to implant children who are too young to consent. Some people think it is unethical -not- to implant a child, because they place a higher value on hearing than I do.
Either way, a lot of people on this forum will agree, the child should be exposed to sign language if they are not already- asap. Even of the child gets a CI, the benefits of learning sign language and communicating effectively will last forever.