If you have access to the email he used, you could use that to reset the password to login. Login at turbotax.com.
If that doesn't work, your fastest alternative is to request a copy of your free federal tax transcript HERE.
Finally, you can request a copy of your return by filing Form 4506. The fee is $30 for each return requested and takes up to 75 days to process.
My deepest condolences for the loss of your husband.