If those medicines were for his personal use (and not to be, paid by the govt), then why did he not ask for a separate bill, one covering  the medicine 'paid'  the govt and the other  paid by himself. 

And, even if he used the same bill, he should have mentioned that the govt is responsible for the cost of just 3 or 4 and he would bear the expense of the other 3 or 4. So I think he is not innocent.