Hello and Welcome to ‘Ask A Doctor’ service. I have reviewed your query and here is my advice. The biggest concern with getting a tattoo is infection and this risk is compounded when on cortisone. So, you are correct, his medications will put him m at greater risk for complications from getting the tattoo. I cannot answer projective questions regarding coming off cortisone just to get a tattoo without knowing his medical history and why he is on cortisone in the first place. Remember, anytime you get a tattoo there is risk and cleanliness of the tattoo procedure and environment is of utmost importance. Thank you for asking this question and good luck to you.