Affidavit of Support I-864.Can a saving account with two account holders be accepted?

[Carlaskipi]

I am preparing the Affidavit for my spouse. We are using our savings and checking accounts for the Affidavit of Support. One of the savings accounts we are presenting is owned by my spouse (the principal immigrant) and his mother (she is not immigrating with us). Can the money of the saving account be accepted even when he is not the only account holder?
One of the account holders is the principal immigrant, the other one is not immigrating.
The saving account I am referring to is from a bank outside of USA.