The requirement is at least 2 months prior application date on a Thai Bank account. If this is supposed to be one account or more is the decision of the Immigration Officer. But be aware that all accounts have to be on your name.
You friend arrived without any visa and used the 30 day Visa Exempt Scheme.
If he did not contact Immigration during his stay, he will be in overstay and face a 500 thb a day fine with maximum 20.000 Thb. Depending on reporting himself at airport Immigration or beeing caught there are other issues to solve.