You might be right... But I suspect that the murder/suicide clause was not intended to deal with this situation. It was probably intended to deal with the situation where the relatives of the person who committed suicide are the ones who are suing. Obviously, you can't commit suicide so that your relatives can make a claim on the policy. But this guy was just an innocent bystander. Different situation, if you ask me.
And the murder clause obviously has nothing to do with it since neither he nor the other driver were murdered.
Unless the law is clear that he loses, I would take it up on appeal, if I were him.
The issue on whether the driver was trying to committ suicide only applies to prove this was an intentional act and specifically denied under the insurance coverage. Go read your auto policy. All insurance is clear that it only covers accidents which by definition are not intentional.