His mother died exactly 6 years ago - Should I email him or not? - TIP

You owe him nothing. It is that simple - You are no longer responsible for his well being or comfort.

That's the default attitude.

Now if you want to take a step out of compassion and send him a one line text message or email, that's ok too, but only if you are ok with him not even answering back or saying thank you.

My advice would be: if it hurts you in any way, don't contact him. Someone else is now taking care of him.