yes there is pity much chance that your son may get nit andhra pradesh as per the previous year cutoff it will seems like it's not possible because it was closed at approx 15000 for general.

you haven't mentioned your category so i can't go more ..and even if you belong to general and not even under ews category there is chance of getting in wait till the last time even go for the spot round counselling there is risk but better will will have higher possibility to get in