Since my husband and I filed together this year, does he need to sign into his Intuit account and file on his own account?

Since you've filed a joint return, you only need to file the return on one account. Your husband does not need to sign into his own account.

No.   When you file joint return your prepare and file ONE tax return that has all of the combined information for both spouses on that same return.   You only use one account for that return.   Your spouse should keep a record of how to access his "old" account in case he needs to look at past returns---which will be saved for seven years.  Otherwise, continue to use your account for the joint returns going forward.  Do not try to change the order of the names on the returns in future years.