First shoot with OCF
The ISO is visible on two of the pics, and it is 800 and 1600. One of the benefits of using flash is to allow for low ISO . Maybe it wasnt possible in your case, but keep in mind that the lower the ISO, the better quality will be the file.
His eyes are still somewhat very dark. Maybe try tl o light them more.
The light from the background is "bleeding" on him. It may be a choice you made, and it is not necessarily bad. But you could try to overexpose less the background, so you wont have the "bleeding" effect.
As the previous poster said, the pictures are not very sharp. Single point AF, with focus on the eye, works ok for me. The shutter speed use is quite long. Maybe a lot of ambient light from the room also comes on his face and makes the picture more blurry. So if there are light sources in the room other than the flash, try to turn them off?
How far is the flash light source from him? Maybe try to get this light source very close to him.