I had a teacher, mentor, who told me about a Hawaiian ritual called Hoʻoponopono, or "the four things that matter most." It's basically just a few key things that we can say when we're saying goodbye to a loved one that can really help at the early stages of loss.
Additionally, "I" statements work better than "you" statements. "I can see how painful this is" acknowledges the reality of the situation and invites further examination. "You need to move on" has the opposite effect.
It's good that your families live close. This becomes a primary relationship now. You're the last witnesses to each other's lives. You hold the memories.
What? Have you been talking to Collins? Not Shakespeare. Luke, the disciple, who probably heard it from Paul the Apostle. But what do I know? I'm Jewish. It's not my book. Shakespeare had nothing to do with it, though.