Can my fiancee put my name on his checking account making it a joint account if he is incarcerated? ?

Unfortunately he was incarcerated with out warning several months ago. He has turned all his financial matters over to me. He signed several blank checks the day he went in, but after they were all gone we have relied on his ATM card & I have had to take care of things with cash. When I filed my taxes this year I did a direct deposit to his account using Turbo Tax, because his funds are running low & it would be faster then having a check mailed to me. I didn't realize at the time that MY name had to be on the account. Just a stab in the dark but does anybody know if he can put me on the account if I have a notarized statement from him saying he wants me on the account? Would the bank have a special form for this? Otherwise it will take an additional 3 to 6 weeks for the IRS to send me my check after the bank rejects the direct deposit.