There's a distinct possibility that the gentleman on the left is a brother, or very close relative. I tried something similar with his image, with the exception of the eyes I couldn't get one to merge into the other without distorting it and making it look ridiculous. Even taking into consideration a person maturing and putting on weight - their foreheads are completely different.
This is only conclusive when you want to prove who someone definitely isn't - if that makes sense. For example, if you placed an image of Lydart onto an image of mine, because the shapes of our faces are totally different we could never be mistaken for one another.
Pels.