I’m hoping you’re implying he should be charged with murder. This might be one of those cases where it is much more likely a jury would find him guilty of manslaughter rather than murder.
So, I looked up Mass’s criminal code, and I think I found why they’re doing this. They have a separate section for voluntary manslaughter without a murder charge, and it doesn’t seem to require them to show the defendant intended to murder, only that they intended to cause the injury. Which like I think he very clearly did intend to murder, but a regular person might get tripped up on that.