Lori,
I'm sorry that your dad developed this painful condition.
I'm not a physician, but from my understanding osteomyelitis results from an infection that starts in the bloodstream, not the bone marrow, so MDS won't cause osteomyelitis, but MDS patients could be more susceptible to osteomyelitis either because MDS has left them with a weakened immune system or because they are immunosuppressed as part of their treatment. Does that make sense to you? What kind of treatment is your dad getting?
Osteomyelitis came up in a discussion about another forum member's father, in the thread named
My Dad's Story.