Elle ne peut pas aller chercher les enfants à l'école. Est-ce que tu peux, toi?
What is the purpose of toi at the end of the 2nd sentence? Is this just common, or grammatical necessity, or translated by "do you?" as short repetition of the question, also this is not possible in German or English when leaving the verb out?
Non, il ne vient pas avec nous. Lui, il va à Strasbourg.
Is the lui here necessary or just emphasis. Would "nous. Il va..." be wrong?
What rule of thumb exists to distinguish the use of lui vs. le/la. Can lui only be used when a verb refers to a person or can I say:
C'est Eric. Je sais il/lui.