Question to Catholics from a non catholic (baby)

I am not catholic so I’m clueless...

My fiancé is catholic (converted only because of step dad) and his mom talked about christening my son (due in October).

Question is:

What’s the process if one of the parents isn’t? I’m not sure I’m 100% on board mainly because my fiancé the entire time ive known him has never attended church never really been involved and again in my highest opinion it’s only because his step dad is and that’s basically who raised him. He converted about 7 years ago or and was mainly done so he could have a part in his parents church wedding.

He claims to be a “traditional catholic” 🙄 but that’s now that we’re having a baby and planning a wedding never did this tradition come up so I’m wondering what a christening really entails along with how it would work with me not being one..

Thanks in advance...