How can he change?

My ex has some serious issues, I’m not a therapist/ doctor so I’m not sure what exactly but he gets easily triggered, he has such a short temper and he flips in .3 sec. he freaks out when he doesn’t have control and it just seems like he always has to destroy everything. He’s so negative and when we were together I would always try to make sure everything was good and we were happy because he has the ugliest side to him.

We’re not together anymore, it just because too much for me and I felt like I started to become depressed/ ugly/ my anxiety was the worst when I was with him. We’re friends now and all I want to do is guide him, I want him to get better for himself. I’m focused on my future and I’m currently happy I just want him to be a better version of himself.

How do I help him?

He swears he wants to change but he’s so lost and doesn’t know where to start.