No, McD's is frucking poison and someone who seems so addicted (and is already in the system) would likely benefit FAR more from the following...
1) Stop eating crap. ie: Learn to cook at home and bloody well do it. It's cheap and good and I pretty much NEVER eat anything that hasn't been made with my own two hands (I also worked in kitchens for many years so know how grody things can get).
2) Make sure you get at least SOME form of exercise. You've mentioned pain issues. Get a local pool membership (you can likely get a discount if you are disabled). Even just bobbing around in the water at first will help. If there are water therapy classes available, take them. Pool shiz takes the weight off of things so you can get some exercise with less pain/damage. Also try to get some physiotherapy and ask the therapist to give you a routine to do at home every day.
Recovery is haaaaaard and tedious work. Do it religiously and life will figure out a way of getting better on its own.
If you are too much of a [REDACTED] to do that then the only advice I have left is...
*fart*