If i talk about my granny, i think things are bit opposite. She is the one who talks spiritual and religious and that makes her positive and out of depression.
Instead, she always tell me not to be depressed and trust in God.
Well you are right, in our society, we leave elders alone and that is the main cause of their depression.
So i would say to love them as dearly as possible. Do not forget you will be at their stage soon