1. The struggling medical student was anxious for his board exams to be over. (May I use about instead of for?) No, you can't 2.The kid is anxious about starting kindergarten.(Does it work if use for to instead of about?) No, it doesn't. 3.We are all anxious to see our grandfather.(Does it work if I rewrite the sentence as: we are all anxious about seeing our grandfather.) Yes, it does. Actually, the three examples are self explanatory of how you can use the word "anxious".

The different meanings of the word "anxious" are conveyed by the different prepositions used. 1) No, you must use "for", unless you rewrite the sentence: "The struggling medical student was anxious about his exams." 2) This sentence means the kid is a bit worried. If you write that the kid is "anxious to start", it means that he is keen to start and looking forward to it. 3) This means that you are looking forward to seeing him. If you are "anxious about" seeing him, you are feeling nervous about it.

liosha, This is how I would use them. Wishing or desiring so much that it makes you impatient, nervous, excited. (for, or to +infinitive) 1. The struggling medical student was anxious for his board exams to be over. The struggling medical student was anxious to finish his exams. 3. We are all anxious to see our grandfather. We are all anxious for the arrival of our grandfather. Troubled in mind, uneasy, worried that something bad might happen (about) 2. The kid is anxious about starting kindergarten ------------- The struggling medical student was anxious for his board exams to be over. May I use about instaed of for? No. The kid is anxious about starting kindergarten. Does it work if I use (for, to) instead of about? No. We are all anxious to see our grandfather. Does it work if I rewrite the sentence as: we are all anxious about seeing our grandfather? No.

Perhaps this doesn't really answer the question, but I wonder if your confusion comes from the fact that 'anxious' can have more than one meaning. Normally, it expresses something negative - worry or apprehension. However, it sometimes has another meaning when used in certain verb forms, like "to be anxious to" or "to be anxious for", when it can, depending on context, mean to be keen for, or to eagerly desire, something to happen. This is the meaning in 1 and 3, but not 2.