I am looking for another idiomatic expression for "bend over backwards" to help others.
"Give the shirt off his/her back" http://idioms.thefreedictionary.com/give+the+shirt+off+back
Fig. to give anything that is asked for, no matter the sacrifice required. Tom would give any of his old army buddies the shirt off his back. You can always count on Mark when you're in trouble; he'd give you the shirt off his back.
"Generous to a fault" https://idioms.thefreedictionary.com/to+a+fault
Excessively, extremely, as in He was generous to a fault. This phrase, always qualifying an adjective, has been so used since the mid-1700s. Indeed, Oliver Goldsmith had this precise usage in The Life of Richard Nash (1762).