I saw this hit when it happened and many times afterward and while it was a hard hit, I would not describe it as 'brutal'. It was not an intentional helmet to helmet hit. The Pittsburgh player led with his shoulder and tried to avoid hitting McGahee with his head. There was contact between the helmets but it was far below the level of hit that Jack Tatum laid on Darrell Stingley. THAT was an intentional missile launch that was intended to injure.
The good thing for McGahee was that he saw it coming. The body tends to deal better with impacts like this when that happens.
I would agree with you on the hit. Not intentional at all. Both are going full steam ahead and in fact McGahee lowered his head at the time of the hit.
Glad to hear they both are okay.