Weak hooves are not inherent in horses. White hoof, black hoof, TB, QH, Arabian. They're all built the same from the inside out. Same as the feral Spanish Conquistador escapee crosses (Mustangs) who live on hard, dry ground.
Despite domestication, you can help him.
-On what type of ground does he live? Stalls and small paddocks harbor urine/ammonia that will eat his hooves. Wet pastures and soggy ground soften hooves, just like fingernails in a lengthy bath. Dry hard ground, sans iron shoes, builds strong hooves.
-Improper trimming (before the shoe) - I.e. Leaving the walls splayed, flared and long, beyond where the inner structures of the hoof can support it. (ever leave your toenails too long in riding boots?) - and driving shoe nails into chipped, overgrown hoof wall can cause the weight bearing hoof wall to fall apart.
-Oiling cracks can attract dirt and microbes into an already compromised hoof wall.
-In his "club hoof" what is the angle of the coffin bone? Some foals grow their heels faster than their toes and they’re incarcerated for life by a fearful trimmer/farrier who refuses to get the hoof out of the way according to the inner structures. A TRUE club hoof is rare. If the tendon is contracted it may have developed out of incorrect trimming. Vets? Can contracted tendons be gradually stretched with careful, knowledgeable trimming? What do his bones look like from the inside?
Poor guy. I (human) couldn’t run track and high jump in high-heels.