No intention, no fault. But definitely unsafe lane change, I think.
But damn, I really have little sympathy for all the inattentive drivers not being able to stop in time for the pileup (and hope damages have to be payed accordingly). Maybe, Tesla FSD does not make the streets more dangerous than they already are, after all.
Nonsense.
He wouldn't be at fault for slowing down (after checking his eyesight).
Lane change is what makes Tesla at fault here, not unreasonable slowing down.