This marks the beginning of another event in the larger story. It may involve different people than the previous events. Your language may have a way of showing this.
This refers to the faith of the men and may also include the faith of the paralyzed man.
# Son
The man was not Jesus' real son. Jesus was speaking to him politely. If this is confusing, it can also be translated "My friend" or "Young man" or even omitted.