Need to Manage 2nd Gophone

I have two gophones, one for me and one for my son. I want to manage his phone online through my myatt account. However, the passwords go directly to his phone by text. Is there a way around this? In other words, can I manage his phones account online without him getting the passwords via text you his phone? And therefore changing the password so I can't see his usage details. Also, how would I get the password since its sent to his phone?

Thank you.