The maintainer did mention mental health issues. It can be hard to say no in the best of times, let alone when your own mind is trying to screw with you.
That's brave on his part and honest. I would never admit that in public personally and shows his personal level of honesty, unfortunately it can make you the victim of even more predators. Just say "no" and move on with your own agenda on your own personal projects. It's none of anyone's business, but one may share at times, just realize that others may try to take advantage. That's just my take.