First, how far away does the string-pulling brother live? Perhaps you could say, "Thank you so much for setting this up for me! It shows you really care about me! However, I'm not able to go, because it wouldn't be safe for me to drive in that kind of traffic. Of course, if you'd be willing to get me and take me there...."

And next, if you are pathetic, then you are a member of a very large club. "Comfort zone" implies inconvenience. You are talking about "safety zone".

I've had a few folks imply that I'm a sissy for not daring to drive to certain places. I know my limitations, and an anxious, fatigued, cognitive-fogged driver is NOT safe, for me or anyone else on the road.

I'll be praying that a way will open up for you.