Gosh, way to go finding and taking care of him. He looks fantastic. I'm actually going to guess that he's cowhorse bred... he looks similar in build to horses like Dual Pep/Mister Dual Pep etc, and something about that head makes me think "cow" too.

Pros:
Excellent body weight/condition/muscle mass
Masculine face
Long shoulder, open angle
Big square hip, low stifles, expressive muscle
Good bone, legs look relatively free from abuse

Cons:
Neck looks a little too long and too heavy for his size
Swaybacked with age
Looks long over the loin
Short and very flat over the croup; high tailset
Right knee looks a little blown up

I like GL's phrase "generously swaybacked" lol and I pretty much agree with what she said (I read hers after typing mine and there are clearly some things we both see)