When his house was being 'stormed' he should have used lethal force. While being kidnapped, he should have used lethal force. By the time he did use lethal force, it does not sound like he was in danger or not in danger from both attackers who were sitting inside a car. The old coot seems to have missed his window of opportunity.
Well, he supposedly HAD a CHL. That will be gone now. Admission of using illegal drugs to a LEO will no doubt get it revoked, even if the shooting turns out to be justified. It is going to have to be a really creative story to justify shooting two guys in the back of the head when they were seated in a car and had only one baseball bat between them. I am not convinced as to where the imminent threat to the old coot's life was when he shot the bad guys. Given the intent, opportunity, and ability, I would guess two guys seated in a car are going to have limited opportunity and ability to beat somebody with a baseball bat who is behind them.