I have no problems with the nanites bring aaron back to life. We already know they heal people, and of all the people who they could save he earned it. Plus they use his code. Maybe they love him.
Which makes be wonder if they are going to make the nanites sentient somehow? Maybe the reasoning would be that there are so many (quadrillions) of them that they collectively are developing a sentient consciousness. So we may see weird shit like the healing of Aaron and power to come on in wierd places etc..