I assume you've spoken to him, but you may need to try again, very seriously.
Find, or create, a time and place with no distractions from DC or housework or TV or anything, then sit him down and really tell him how you feel, as honestly and calmly as you can. Try your best not to lay blame or accuse, try your best not to get angry or lose your temper, and do admit fault when it's there (without taking undue blame for things that are not your fault). Ask him questions, listen to his answers, and let him tell you how he feels as well. Make sure he understands that you are very serious and that this conversation could determine the future between you.
Tell him that, while you do not want to, you are thinking of ending it with him and will do so if some things don't change. Make sure he understands this is a very serious conversation he must participate in, that you expect total honesty from him, and you will not tolerate him turning things around on you to get out of it. Then tell him all that you've told us here, that he has not sought help for his PTSD and how you feel that is affecting the way that he treats you. Tell him that you feel alienated and alone, and feel that there is no friendship between you any longer... everything you've told us and everything else that you haven't said here.
Tell him that your happiness and the love between you has not been a priority for too long now, and that is unacceptable. Nothing is more important and everything else can and must be set to one side, if even for a few minutes each day, in order to focus on US. If he is unwilling or unable to do that, then here are the options: stay in an unhappy marriage and continue to deteriorate; leave and start all over, with all the logistical and emotional effects of a divorce; or re-prioritise, make some small changes, and work toward improvement.
Find out whether or not he understands how you have been feeling. Find out if he is equally unhappy or is somehow fine with how things are going. See if he is willing to make changes, and if so, which changes. Ask him flat out if he would honestly be ready for you to end it all and split for good.
We were having a rocky patch in our marriage recently, and that's what I did. It turned out that he really had no idea how serious my problems were, how angry I was or how alienated I felt, nor how close we were to the very end. When we really sat and talked about it, concentrated on each other, listened and exchanged thoughts, and both tried very hard to not be accusatory but to really open up, we were able to work out a great deal. Things changed surprisingly quickly after, and now we are happier than ever.
However, we were not dealing with everything that you are. I know that PTSD can be overwhelming and incredibly difficult to deal with, and I know that the causes are often so personal that they feel impossible to talk about or work through with somebody else. It can be so painful, so terrifying, and so all-consuming that me may honestly not be able to see through it to how it's affecting you. Of course, a simple conversation (or series of conversations) between just the two of you will likely not solve the root of his problems. If you can convince him to get help, however, things could change. Perhaps that's where you can start with a serious conversation - him seeking help for his PTSD.
Re selling: I don't know enough about the condition of your house, but if it's in the middle of renovation, it may actually be worth less than what you paid, which could cause financial problems for the future. If you don't think you can work anything out between you, you should see an agent about the house if you are worried about the condition it's in or the value. Get a professional opinion there, then see a solicitor for advice about working that into a settlement if things simply cannot improve between you.