SUBREDDIT: r/relationships
TITLE: I[17F] don't know how to deal with my Bf[24M] being gone for 4 months.
POST: My boyfriend and I have been together for about 5 months. Everything about him meshed so perfectly with me. He's an ex Sea Bee, currently working on getting his GED. He's dealing with PTSD and some severe depression. When he got back from deployment, he became homeless and has dealt with a ton of shit. He was checked into a rehab facility about 2 weeks ago for a 4 month program. 6 days ago his phone was shut off because he couldn't pay. 

I'm a very codependent person and being away from him for this long just seems impossible. How can I deal with this? Is there anything I can do to make it seem not as long? 

Before you comment on the age gap, both of our families approve, and it's like we're two peas in a pod.
TL;DR: 
Bf has PTSD, in treatment facility for 4 months, his phone is off and I dont know how to cope without him.