I can see where you were going with this having taken several photos of my father similar to this. It's hard to get that thoughtful , far away look . I think you almost have it here, but his expression is a bit tight, making him look pensive or worried. Still a great character profile.
For me, I wonder what this would look like if it was cropped in more on the left hand side? I like the naturalness of your model. Reminds me of my Dad.
I would like to have seen the face closer with more focus on the details. Also, he shouldn't be looking towards the sunshine if it is so strong he has to squint.