He could have been going to turn right though. It was clearly his fault imobecause he didn't indicate, it was his responsibility to provide information for other road users.
He obviously hasn't looked in his rear view mirror or his near side wing mirror either.
He should have checked his rear view mirror so he was aware of traffic around him, braked, indicated left, checked the other side of the road was clear then swung out, checked his nearside mirror then carried out his left turn.
That would all come naturally to me tbh, when carrying out a manouver where you have to swing out so much you make sure all over road users are aware of your intentions and you observe all around you.
However insurance may say 50/50 because they don't want the hassle of a dispute and both parties have cars with little value.