Deb,
Well done! Thanx for posting.
What you've probably realised here is the diffiulty of shooting in leafy backyards; the mottled lighting on the first two can be a nice effect, but at the same time some might consider that it detracts from the portrait.
Let's deal with the third image first: the driveway (or is it a footpath) is heavily blown, but that's fine; you're shooting your son.I would like to pull the exposure up a tad more, lightening his face. You could use a mask in
PS to pull the path back down.
To address the problems while shooting (usually the best way, IMHO) I would have either used the on-camera flash to add light within the shadows (adding more light to your son's face) or a smallish reflector to pull some sunlight in to do much the same job.
A suitable reflector can be made from, say, a piece of white foam core board, either as it is, or else covered in well crinkled but flattenned aluminium foil. The deal is that you want to have a reflective, but not bright or shiny, surface.
Your assistant (gotta get your man involved, haven't we?) would be out of view, and holding the reflector so that a small amount of additional light can be directed onto your son's face.
The first two images are much more difficult to deal with, because the mottling is right through your son's face. Relocating him to a less difficult position might, or might not, be a viable option.
Presuming it's not, use the reflectors again (see why I did that image first?) and take a spot meter reading off your son's face (or neck or shirt, based on these images) from the areas getting the brightest light. Use that reading as the starting point for your exposure, as you really don't want to burn that part of the image out.
Your goal is not to get a constant exposure across the image - the mottling indicates that won't really be possible - but more to try to reduce the effective contrast range that the image traverses.
After taking the first image, use your histogram and move the exposure range one way (or the other) a little bit to try to utilise as much of the available contrast range as you can.
Please feel free to pull me up if there's stuff here you don't understand; and thanx for posting and sharing. You have a handsome young man there; I'm sure he'll become a real handful over time.