Hi Nancy Ellen,
Wow... you do have a lot on your plate.
I cannot possibly know all of the dynamics of your situation or your brother's level of commitment to sobriety but I do know that even if he is fully committed it is a hard road for most to make successfully.
You could twist yourself into a pretzel, run yourself ragged taking care of his responsibilities, your own and care for your aged relatives and he could relapse at any moment (if he actually makes it into authentic recovery)....
So my ES and H is that anything you agree to do to help him is very carefully designed in a formal recovery plan that has clear cut boundaries and benchmarks and agreements by him as to what he will be doing to initiate and complete his recovery plan.
He needs an evaluation by a treatment professional who will help design an individual plan... he may need inpatient or residential, outpatient, detox... and I do strongly recommend AA and the 12 step program (the whole enchilada not just meeting attendance but completing the steps with a GOOD sponsor).
Set boundaries for YOU... what you will do or not do and that you will immediately cease all helpful acts if he violates those boundaries.
And if you choose not to get involved in something that is not your problem or will create problems for you there is nothing wrong with that either.
Only you can decide what is best for YOU and if you want to help him anything.