Ask HN: What IT skills does a Product Manager need, to be effective and respected?

An acquaintance of mine works as a product manager at a small credit union's IT Department in Los Angeles. He says that his engineers don't respect him and he feels that they don't consider him to be a good product manager.

So he contacted me earlier this week and said he wanted to learn to code, primarily so he can be competitive in the coming years and then asked for recommendation on languages.

I don't think a good Product Manager needs to necessarily learn to code. Not sure what to tell him.

Can anyone tell me what skills or software products a person needs to be good with, in order to be an effective Product Manager at an IT Department of a Bank (not a Startup / Saas Company, I know a Product Manager there would be quite different).