Answer:
Because he was an HIV carrier.
Step-by-step explanation:
Andrew Beckett was an HIV carrier, so he had the disease we know as AIDS. Beckett knew how intolerant people are with the carriers of this disease and for this reason, he hid that he was infected as much as he can, however, as time went by the news of Beckett's disease surfaced and as he imagined, he suffered several types of discrimination, disrespect and prejudice.