Uh, I dont know for sure but my guess is no he can not grant amnesty. I mean a Pardon from prison due to a criminal conviction is different from allowing people to become permanent residents and or citizens. Even if he did or could, I think something like that would go to the supreme court, or congress would attempt to act on it as well. But its hard to say, I guess since he is the executive branch, he could just stop enforcing those laws… but that has complications of their own. Also in all honesty, looking at this from a political perspective, if he wants to get anything done in congress he will do his best not to completely alienate one side or the other.