His best friend really felt like a convenient plot device or that "one in a million guy" at best. I like the father the most, he felt believable and real. It seems mostly to be a generation thing with him and it's understandable that he wants to keep him (or her in his mind) out of harm. You can't expect old people to make a 180° turn in a few days if they have lived that way for 50+ years.
If Chiaki were a girl, it would make sense not to make her too tomboyish. Basic men usually hate this and who wants to marry a hunter if they actually want a house wife? His only problem was that he didn't really ask his son in the first place and just did what he thought was right because "parents know better".