Son-in-law to be?

I'm writing a story where there are many characters who are son/daughter/(etc)-in-law to be. Is there a proper way to write this down, rather than to be?

 

Other than "lambs to the slaughter"?

 

Yes, other than that, I suppose so. Though it is a great definition.

 

the usual way is 'prospective son-in-law'... or 'future'...

 

Oh, thanks a ton!

 

Who is referring to them in this way? Parents would probably call their future son/daughter-in-law some variation on "Jill's fiancé" or "Tim's fiancée." Parents are going to be much more concerned about that person in relation to their child rather than in relation to themselves.

 

Only if the future son/daughter-in-law is lucky. More often it's "him" or "her", with a slight huff, or "that bum/golddigger/<insert disparaging label>".

 

Not in dialogue, but in narration. My style of narration is sarcastic, and sometimes I cannot use XYZ's fiancé etc in the narration.

 

If it's sarcastic, then I think Cogito has given you the best suggestions!

 

That's why I'm trying hard to ignore him.