It sounds as though the dilated cardiomyopathy was probably viral. It's certainly a good sign that his LVEF has raised to 27% from 13% in just a few weeks and there is no way to determine if this trend will continue. Ensure he keeps to his medications and don't let him exercise too much. I would certainly consider the Defib implant because if his heart stops, then it will be restarted immediately. If his LVEF continues to improve, then this is just going to be a temporary measure anyway. Now you ask about survival which is understandable and I do sympathise with you. Thanks to new medications, many people with DCM now live normal lives. With his EF at 27% he will still be around in 2 years. I would wait a while before considering a transplant, in case his EF raises again. If it goes above 30% then he is no longer classed as heart failure and 27% is pretty damn close to that. So rather than go through all the risks involved with transplant, and the problems of fighting rejection, I would seriously hold off from that option for now. If his EF doesn't drop again, then I would probably forget that option altogether.
I am very sorry such bad health has struck.
I think you need to take steps to be put on a heart transplant waiting list. I do not know anything about how to do that but heart doctors/hospitals and even the "Web" should be able to provide guidance.
A defibrillator may be something that can be done soon that will automatically help restart the heart should it stop.