I don't think he will absorb it.
Honestly, if he does, it'll be too much.
I just think Obito will be more aware of senjutsu later. Really, if Obito wanted, he could've killed them all already.
He's just playing with them.
And I doubt Obito would turn into stone because he absorbed senjutsu. Why?
Well, it's because he has too much chakra. He'd only turn into stone if natural energy > physical energy or spiritual energy.
But Naruto wouldn't be able to do that, overload Obito with Natural energy, that is.