Whether that theory is correct or not, and I'm not sure it is, is really moot. The fact that either V1 or V2 had to change lanes to avoid D1, indicates D1 did not have enough space to make the turn and acted in an unsafe manner.
From previous accounts, it would appear that V1 and V2 were in adjacent lanes, not the same one. This would be borne out by the fact that there were three lanes and no other traffic so there was no reason for V2 to be in the same lane and tailgating V1. My theory is more that V2 was slightly behind and to the curbside of V1. At that angle he didn't see D1 until V1 swerved to avoid D1.
But that still means that D1 did not have enough space to make the turn. This is also complicated by the fact that D1 was making a right turn, which means V1 and V2 could have been in her blind spot since she was facing in the same direction. But that doesn't excuse D1 it just means she should have been more cautious.
I'm just trying to give you the perspective of what would happen if this claim to court.

