You have read me right Janie. When I wrote "chemical imbalance", I was referring to that complex and imperfectly understood cocktail of physical and possibly metaphysical forces, which compels people to think or act in a certain way. We constantly remake and adapt our models of the world, but sometimes we are tempted to forget that our models are only that. Of course, there is always every reason to try and improve them.
I have been in contact with my brother. One of the things I said was that although it may appear to him at times that suicide would end his problems, it would only just be the beginning for those left behind. I know it is a selfish angle, but I know he loves me and he would not want to deliberately inflict that amount of suffering on others.
I hope I can persuade him to get professional help...
Thanks for your time.