[rwairforce]

"Makes me feel "real good" doing this to him."

You are doing nothing but taking care of him. You are not "doing this to him", life does this to everyone that lives long enough.
You are a fine son taking care of him and doing what needs to be done, even if it isn't what you would like to do.
We can't always do what we want to do but reality dictates certain actions and I would say that you're doing a very loving thing.
Of course you can't take him to the woods and shoot him, those were just words made long ago, we've all said such things.
Keep up the good work and know that you're doing what needs to be done and doing it with care and love in your heart. What else could one ask for.