The only men Raiola cares about are Raiola and Raiola's client. If United is not playing ball well enough and on time, he'll be happy to take his client to Chelsea if Chelsea shows enough intent and is ready to spend without restraints. E.g Chelsea is happy to pay Arsenal for Sanchez, pay Raiola for his agency fees and pay whatever wages Sanchez wants. Perhaps the biggest obstacle to Mikhi going to Arsenal is wage related. Is Arsenal ready to pay Mikhi? He currently gets about 200,000 pounds a week at United. He'll probably ask Arsenal for something closer to 300,000 pounds per week. My guess is that Arsenal will be reluctant to pay him that kind of money. Chelsea on the other hand, wouldn't mind.
I think it comes down to how badly United wants Sanchez. The club will certainly have the option of 'buying' Mikhi off if Arsenal is reluctant. But then, that will make the Sanchez fee begin to look excessive.