"the personal accounts are Rollover IRA,"

"Rollover" is how it got Funded. That would likely be a Traditional IRA, then.

"regular IRA,"

= Traditional, as well. The brokerage might have allowed the person to send their Rollover to that existing Traditional IRA account, or combine them now. They are the same concept.

"and SEP IRA."

Again, a brokerage might allow one "sheltered" account to hold all Traditional, SEP and Rollover IRA funds of that same type = falling under the same regulations. Or, once they are no longer operating the C corp, the would "transfer" the SEP IRA into the Tradition IRA, to reduce the number of accounts they manage. That's why you need to know the Types of accounts.