Take action and DO something meaningful in his or her name. Even of its as small as dedicating a song or poem. This is better than platitudes. When I go out, instead of thoughts and prayers I would love it if everyone brought their favorite song that reminds them of me.

Hugs, great big body encompassing hugs. So much emotion can be put into a hug and it can be very grounding for the person who is suffering.

As others have said tell them you are sorry for their loss, look for ways to offer to do things for them, babysitting, preparing food, cleaning, driving them places, feeding/walking pets. Many times people are not even sure of what they need make suggestions to them of what you can do to help.

Let them know you are there and ready to listen.

It is a horrible time for your family.

Loved all the answers below

My condolences for your loss.