How to Forgive Those Who Hurt You Deeply!

My father has a short time to live. How can I effectively share the gospel with him when he doesn't seem open? My mother is in a memory care facility, and this has caused a rift between me and my sister. I wonder what to do! Can you explain the "left behind" concept again from Matthew 24 and Luke 17? How often should we do the Lord's Supper? What about claim we shouldn't do it at all?