Glad he came through his neuter fine; he does look quite out of it.
He seems so similar to Deacon! Yes, undescended testicles are fairly common in shelties; Brodie's just just prior, Deacon's, as with Pico, was settled comfortably in his abdomen. Note... Deacon still, at 3, will not lie down for me to groom him on that side even if I am tender with it. I did the suit when I could supervise and the suit with a donut (more comfy than a cone) when I could not. Recovery time is longer due to that abdominal incision, but I bet he will be feeling better in a few days and then the struggle to keep them quiet begins!
Guess it comes from my days with doxies, but being slim and trim is a positive thing in my eyes. Deacon is maybe 14" and weighs 16 lbs. When wet he looks like a whippet - he has a VERY thick coat and is about 6 times the diameter when dry. I monitor my boys weight very carefully. My trainer uses the hand... held open, palm down, run your opposite hand across the stationary one - that is the feel you want with the rib cage. Flip your hand over, run your hand across the your knuckles on the palm of your hand - that is an overweight dog. Make a fist and run your knuckles across one final time - that is an underweight dog.