Easy, the same way they deal with their existing employees. It'll be the IBM way or the highway. We'll see the usual repetitive and doomed IBM strategy of brutal downsizings accompanied by the earnest IBM belief that a few offshore wage slaves can do as good a job as anybody else.
The product and service will deteriorate, pricing will have to go up significantly to recover the tens of billions of dollars of "goodwill" that IBM have just splurged, and in five years time we'll all be saying "remember how the clueless twats at IBM bought Red Hat and screwed it up?"
One of IBM's main problems is lack of revenue, and yet Red Hat only adds about $3bn to their revenue. As with most M&A the motivators here are a surplus of cash and hopeless optimism, accompanied by the suppression of all common sense.
Well done Gini, it's another winner.