In the sentence you wrote, "would" is similar to "could", but there is a difference.
"he would be" means the speaker trusts that the man will be a good father figure, if there is such a situation.
"he could be" is slightly different because "could" suggest the man is capable of being a father figure, but there is not a definite certainty that he is going to be a good father figu
Yes. Person who has said that believes that he (who is going to be a father) will be a good father. Would is a modal verb. Would has pretty enough modal's contrasts which can express insistence, wish, probability, polite request and preference.