I am trying to file taxes for my sister who is ill. Can I do it on my account
No. Online is only good for one return per account. But you can use the same email address for 5 accounts.How to start a new online returnhttps://ttlc.intuit.com/community/using-turbotax/help/how-do-i-start-another-return-in-turbotax-online/00/25596