Isn't it just like an old man to go chasin' after the younger women?! As for him thinning out in the hind quarters, he might be a bit but he actually looks pretty good to me for his age, particularly with his navicular. Tell that lady friend of his she's doing a great job keeping him moving!
Looks like some "old man sag" going on in his back there, but that could just be the position of his hind quarters/rise of the ground. His muscling, coat, and overall condition look great! Are his legs sound? Can he still be ridden? I'm a firm believer that the longer they have a purpose (within...
If the groove's gone you're looking at closer to 30. And yes, I agree that wolf tooth is worn quite a bit, so yeah ... probably closer to 30. What condition is the horse in otherwise?