Having a break usually means having a BREAK - in my opinion anyway. If he was still in contact with you even 'as friends' can't you see that that would not be 'having a break'?
He might be keeping his distance because he feels he revealed too much too soon; he might feel over exposed and incredibly vulnerable. It might be he needs a chance to reevaluate the relationship you have and yes, as hard as it is, it might mean he decides he doesn't want a relationship with you (or anyone).
I understand it will be very painful, but I really hope you DO respect his space and don't txt or call him, or go to see him. When under a lot of stress due to PTSD, it can feel we are under TREMENDOUS pressure, and not giving him space is only likely to result in him running faster in the other direction - and / or him resenting you for 'pressuring' him.
I think the old edge "if you love something, set if free, if it comes back to you it's yours; if it doesn't, it was never meant to be" applies here.