nope.   

He needs a dependent for HOH, the only time you can file HOH without a dependent is in divorced or separated parents and the custodial parent allows the non-custodial parent to claim the child as a dependent, you cant do this when everyone lives together since they are both custodial parents in the same house.

That was my read also but he swears he read on line that the could take hoh and she could claim the dependent.  Thank you.

Again, if they didnt live together that is a possibility.