Plan on being there in the long run, when the funeral is over, everyone has gone home, the flowers have faded, and the casseroles are gone. My best friend died in a car accident the weekend that we graduated from college. The 20-year anniversary of her death was last week. I had her mom over for dinner yesterday. Talk about their daughter. Share stories that you remember about her, and let them talk about her. Check in as significant dates approach - her birthday, holidays, the anniversary of her death - and see if they want to do anything that day. Some years my friend's mom has wanted to get out of the house for lunch on one of those D. and sometimes, she just wants to stay quiet at home. Send cards just because. If something reminds you of their daughter, send a text and share it...my friend loved sunflowers, so if I'm out an about and see a cool sunflower image, I'll send it to her mom. If you have children the same age, include them just as you always would have - invite them to graduation parties, showers, etc. My friend's mom, who has become a good friend, has always said how much it means that we haven't forgotten her daughter and her (and her other children). She loves to share memories of her daughter with others who knew and loved her. It's painful to remember, but more painful to think that everyone has moved on and forgotten.
In the immediate aftermath of my friend's death, her mom (who was divorced and had no spousal help) was lost in her grief. She didn't sleep, didn't eat, and basically gardened day after day until she was exhausted enough to sleep for a few hours. It was really horrible to watch and know that there was nothing anyone could do for her except to be there. It took well over a year for her to become a functional person again, to resume her own education (she was in law school when her daughter died) and live her new normal. They'll have many years of grieving ahead of them, so plan on being that good friend who remembers when others have moved on.