He does eat raw, 100% of the time, RMBs one meal, mush the next.
For Greyhounds their teeth issues are genetic (which is the same thing with many toy and bracchiosephalic breeds). They have genetic horizontal bone loss, which causes the gums to recede to a point where they have A LOT of tooth exposed that needs to be protected with the harder enamel, and that doesn't happen.
Also, because they are open mouthed breathers, the exposed tooth sections get tartar build up in less than half of the time it normally happens. Many Greys also have genetically soft teeth.
Wally's mouth is the worst I've seen in a Greyhound yet. Though teeth problems are extremely common in Greys, Wally's mouth is not the norm . . . nor is his breath *vomit*