Not really a factor - each share has the same entitlement to future cashflows and dividends, regardless of how many shares the majority owner holds, just like any other company with a large majority owner (see NZ power companies and airNZ etc - all majority owned by government)
When MCK returns to normal level of operations and profitability and returns to paying out majority of cashflow as dividends - no one is going to care how many shares the majority owner has - instead they will be looking at the cold hard cash return.