Brad,
There is ALOT of similarity in facial features between your picture and the other individuals! Honestly, there is more similarity between yourself and that individual then my biological father and myself. I am serious in saying that. I would be very surprised if you are not related.
(As I age, I look far more like my dad then I did with my earlier photos compared to his comparable age photos. The photos of my dad's dad and mine look far more alike. And the photos of my son with my dad look far more alike. Meaning grandson/grandfather similarities in features more then dad/son features.)
I know this is a deep and serious longing of your heart to connect with your bio-parents and seek some measure of reconciliation with them. I hope that this man will consent to the DNA test. I can NOT imagine not wanting to know if I was your father being in his position? What a privilege it would be to have the opportunity to seek some measure of reconciliation with an estranged son. That would be a remarkable and truly beautiful experience! I could only see you bringing good to this man's heart, so I don't know what he would be afraid of?
I am wondering if it would be possible to offer both forgiveness and some documentation to release him from any legal obligation as an incentive to get him to take the DNA test? Maybe convey that you currently expect little of him other then some needed bio-information and wanting the privilege of having some small measure of reconciling and having snapshots (information) of one another's life?
My respect and best regards, Jeff