[Alex80]

Hello everyone!
In the following sentences, when the noun is at the begining of the first sentence, the relative clause should be the second sentence:
1.The boy is cute. He lives next door.
=The boy who lives next door is cute.
2.The novel won the prize. It pleased a lot of writers.
=The novel that pleased a lot of writers won the prize.
3.Tom still rides a bike. He is 84.
= Tom, who is 84, still rides a bike.
*But this rule doesn't apply on the following:
The man stole the money. He must be punished.
= The man who stole the money must be punished.
(The noun is in the first sentence. The relative clause is the complement of the first sentence though.)
Not: The man who must be punished stole the money.
I mean, aside from the meaning, is there any grammatical rule we can depend on?
Thanks in advance