Please take this in the egalitarian spirit it is given.
I note that this is a mixed race family. In my admittedly dated experience as a portrait printer, I came to the realization that different people of different racial and ethnic backgrounds have different preferences with respect to how their skin tones should look in prints, and that those preferences seem to vary when they are shown with people who have the same racial and ethnic backgrounds than when they are shown in a mixed race group.
If you are going to make a print that big, I think you would be very, very wise to print up at least three smaller (8x10?){ versions - lighter, normal and slightly darker - and ask for their feedback.
You may very well receive feedback that the son looks great in one, the mother looks great in another, and the father looks great in a third. I would use the editing tools available to make everyone happy.