How do I give my boyfriend a wake up call about his behavior and need for mental health treatment?

My (30F) boyfriend (30M) of 6 years has been under a lot of stress lately and as a result has had a lot of angry outbursts. He’s never even raised his voice at me but for an example if our puppy has an accident he would yell, slam items around, and just have an aggressive demeanor. It is never directed at me or anyone else but an outwardly expression of anger nonetheless. It is directed at me in other ways though as he will make snarky comments towards me or reply to text messages in a way that is clearly driven by anger. He’s never insulting or anything, it is just his tone and the way that things are said or wording of things. I have PTSD from my father and a previous relationship so that may also be influencing my perception here however I have a lot of self awareness, coping skills, and put in the hard work on my own mental health on a daily basis. My boyfriend is well aware of my PTSD diagnosis and I’ve also shared anger is a huge trigger for me and how I don’t appreciate his snarky comments or snappy responses.

I know he truly needs to deal with the root cause of his angry outbursts as this is not the first time he’s went through a period of time like this but he is stubborn and doesn’t take the initiative. I’m at my limit with this as his unpredictable outbursts are taking a toll on my mental health and stability. I’m currently keeping my distance after he snapped at me for asking a simple question today. I expressed that I need some space to process and ground myself and explained why I’m upset. Is there anything more I can do to encourage him to seek treatment and/or give him a wake up call that he will lose me if this behavior continues?

How do I give my boyfriend a wake up call about his behavior and need for mental health treatment?
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