You may be right from a design point of view...however did your daughter-in-law ask for your opinion???? If not--beter to not offer an opinion.

Let her have her own decisions but encourage him to contribute his own taste

Your daughter-in-law's overall investment in a kitchen remodel depends largely upon the neighborhood she's in. One never wants to over-improve for the area's real estate value, nor do you want to under-invest. If the neighborhood is modest, keep the investment modest. Today's laminates are not bad at all. Or you can look into Corian or quartz. (Quartz is often as expensive as granite though). If the area is a desired area, perhaps granite is the wise investment. There ARE "cheaper" granites, generally those that have a uniform pattern. You may want to visit your local stone yard to explore the possibilities.

Having said that, if your involvement in the remodel is welcome & requested, then fine. If not...please resist the urge to "help".