[For]

Does the 'for you' change a thing?

Your hands are too dirty for you to be touching the food.
Your hands are too dirty to be touching the food.

Does the 'for him' change a thing?
John called Sam to give him the code to the safe - John knows the code.
John called Sam for him to give the code to the safe - Sam knows the code.

Does the 'for me' change a thing?
When people call me from downstairs [for me] to open the building door, it never works.

Thanks