PTSD (and physical illness) is a reason for finding things a struggle but it's not a licence for shouting, snide comments or other negative behaviour. It can happen, of course, but I'd be wary of it happening without your wife wanting and trying to change. A repeating pattern of difficult behaviour/apology/quiet then difficult behaviour again is not going to help either of you.
I think ProudWife99 and LizardViolet have healthy approaches. You need to agree a way together to communicate when either of you is not able to behave reasonably or respectfully enough, and then be able to take time out until you can. And you need to stick to what's agreed and not vary from it.
I really think having counselling has to be the free choice of the individual, but your wife is more likely to make that choice if she realises she can't continue getting by without it by relieving her feelings in this way instead.
I think ProudWife99 and LizardViolet have healthy approaches. You need to agree a way together to communicate when either of you is not able to behave reasonably or respectfully enough, and then be able to take time out until you can. And you need to stick to what's agreed and not vary from it.
I really think having counselling has to be the free choice of the individual, but your wife is more likely to make that choice if she realises she can't continue getting by without it by relieving her feelings in this way instead.