These are a few responses, NOT TO SAY...
"You'll get over this."
"I've been there."
"It's for the best."
"You can always adopt."
"You are lucky that you had your mom for as long as you did. I didn't have my mother for as long as you had yours."
Keep in back of your mind that your friend or family member needs understanding, comfort, solace, "a soft place to land." They know that what happened can't be changed. It is..what it is. And, that it is so sad and painful. Let them know that you're there for them. To listen and to acknowledge. Some better responses:
I am so sorry that this happened.
I was so sad to hear the news.
How are you dealing with this?
May I call you (choose a daily, weekly, biweekly, monthly schedule of communication)?
The moral to this is not to communicate that you know what they're going through, or, that you have the solution. The best is to BE THERE..LISTEN..OFFER HELP (cooking, cleaning, helping with their small children, helping with property clean-out). I know of someone who kept paying the property taxes and minor utilities emptying their father's empty house for years! Was this extended grief? What could you have offered?
*Family members can, and often, includes, pets