Matthew and Mark's accounts are almost identical, except for a few differences in phrasing, but neither of them says a word about Jesus entrusting his mother to one of his disciples, nor his forgiveness of those who hung him on the cross. This should not surprise anyone who has ever told a story in the presence of someone else who knows it. He wasn't praying. He was rehearsing what he was about to say. I couldn't take my eyes off him.
Different people see different things.
Matthew and Mark agree on the first of the seven last words. The next three come from Luke's gospel, and the final three from John's gospel. Each of them shows us a different side of Jesus' death. Each of them shows us a different side of ourselves. The first word is easily the most awful one.