Credit card is not a type of proof of income i think
YES! Your mom can apply for a new line with Globe using her credit card statement as her proof of income. So please advise your mom to bring her credit card with her and her latest 2 months credit card statement upon application on the nearest Globe store.
However your mom may be required to submit 3 additional requirements as follows.
1) Proof of Identification
2) Proof of Billing
3) Proof of Income
For your NEW Postpaid line requirements and the complete list you can check it on the link below.
For EXISTING GLOBE Postpaid subscriber you just need to present a valid ID (Company ID or any Government issued ID) and a photocopy of it.
Hope this helps. Thanks.