there are exceptions for families:
copied from bangkok bank app:
> Eligible Groups for Exceptions and Required Documents
In case it is inconvenient to change the ownership of the mobile number, you can contact the bank branch to request an exemption from today onwards. The eligible groups are:
Families: including parents, children, siblings, grandparents, and registered spouses. Submit the following documents at a bank branch:
Relationship documents: documents issued by Thai government agencies or the state of that country, such as a house registration, birth certificate, marriage certificate.
Documents proving ownership of the phone number, such as a tax invoice or phone bill receipt.
Individuals Requiring Legal Guardianship: Such as incapacitated persons, quasi-incapacitated persons, and persons with disabilities. Submit the following documents at a bank branch:
Court order
An ID Card for PWD (Persons with Disabilities) or document issued by the government agencies, or an officially certified documents.
Legal Entities: Companies, government agencies, or other legal entities (in cases where the mobile number is registered under the name of a legal entity and used by personnel within the organization) must submit the documents at a bank branch as follows:
A letter of certification from the company stating the employee's name, mobile number, and authorization to register the phone number with Mobile Banking.