helping others

I understand that we are all responsible for our own thoughts, feelings, actions and results. But how do we help each other. My son has clinical depression but he takes responsibility for himself and seeks counseling, etc. However, his wife is having trouble with depression since her pregnancy and the birth of their daughter and she won’t seek help. It’s become debilitating. What’s the best way I can support my son and his wife? Other than loving and being compassionate I’m not sure there is much I can do to help her because she’s not open to it. However, my son is very open to learning and growth. What suggestions do you have for supporting him in a way that is helpful and not enabling? Thank you!