Question about etiquette when there is a big age difference between friends?

That's tough because he needs a friend, but she is his mother. Sometimes parents can be blind to the needs of their children, especially if they are the ones imposing the pain. Can you talk with his mom? If at the very least, you should let her know that even if it is not you, her son needs someone to talk to because of all that is going on in his life. She is his mother and is concerned about what she doesn't understand is going on - and as a parent myself, I know that the parent's wishes trumps everything, especially with a minor. If she doesn't want you to have any contact, you need to respect those wishes. You may get yourself into trouble if you don't. Just let her know that you care because you have been through similar cirstances, just be honest and forthcoming with her. I will be praying for all of you.