If the son is not around to raise the child it's a bad and selfish idea.
Presumably he intended to save it to have the option later to use it if that's what he decided to do. That's very different than consenting to allow a donatee to use it.
I’ll admit that there could be a cultural component that is in play that may change the perception where they live.
The sister has even volunteered to be the surrogate. Hopefully it's a gestational surrogacy.