Excel VBA - Get parent window of worksheet

I have a Sub that inserts a header from a template and freezes the top row of the active worksheet, which is written as,

Sub HeaderInsert(headerTemplate As Worksheet)
    headerTemplate.Rows("1:1").Copy
    ActiveSheet.Rows("1:1").Select
    ActiveSheet.Paste
    With ActiveWindow
        .SplitColumn = 0
        .SplitRow = 1
        .FreezePanes = True
    End With
End Sub

I want to turn it into a function which is passed the sheet to insert the header into. So that it would be written,

Function HeaderInsert(headerTemplate As Worksheet, contentSheet as Worksheet)

ActiveSheet becomes contentSheet, but how can I get the Window of contentSheet?

Also is a better way to do that copy and paste?