Are you the executor of his Estate? You need to have legal authority to file his return.
Online is only good for 1 return. But you can use the same email address for 5 accounts. How to start another return in the Online version <a rel="nofollow" target="_blank" href="
https://ttlc.intuit.com/replies/3288574">https://ttlc.intuit.com/replies/3288574</a>
