I'm twenty years older than you, Matt, and have had a few minor calamities along the way. From my perspective, the older you become the more rigid should be an exercise schedule. Not harder, of course, but you must keep at it religiously, session after session, or you will slide into a decline from which there is only a slight chance of regaining strength. Jack Lalanne exercised every day until his mid nineties, and there was a feature a few days ago in the Denver Post of a man in his late nineties going regularly to the gym and feeling good. Climbing is an activity one can theoretically do into old age, since technique and style can compensate for diminishing strength. But in my case severe shoulder arthritis intervened a few years ago, limiting motion and sometimes painful. Nevertheless, I kept at bodyweight exercises and usually feel invigorated after a workout - deceptively youthful, in fact. It's an illusion, but much better than the alternative.
I've broken rather a lot of myself and can only echo what Mr. Bomz said above:
I'd say to have more small term goals than big when recovering. It's good to see the big picture but when you are broken too much of the big picture is overwhelming.
It's great to have a picture in your mind of one day being able tackle the goals you had before the injury, but when it takes everything you have just to move your leg a few inches, it is better to focus on moving your leg half an inch further today than yesterday than to worry about whether you'll climb K2 next year.
The 'illusion' jgill speaks of has kept me strong and returned me to health through many trying times.
Perspective and attitude are within your control.
Be consistent with your training and know this will benefit your progress. When motivation evaporates, put your head down and keep working, knowing that this is what you need to do to return to health.
Be selfish and stubborn with your health. Hold onto it as if your life depends on it.
might want to look into using growth hormone (HGH) or if that is too hard to find (it is illegal after all) then look into these injectible peptides: CJC1295 without DAC, GHRP2, GHRP6, and Ipamorelin. You need the first one and one of the latter three combined together as daily injections 2-3 times. This will boost GH levels to that of a 20 year old man and your recovery will astound your doctor provided you are doing it in conjunction with rehab exercises and a sound diet.