I looked at the previous threads regarding this topic, but they have not helped solve the problem.
how to read password protected excel in python
I don't think that named parameters work in this case. So you'd have to do something like:
xlwb = xlApp.Workbooks.Open(filename, False, True, None, password)
See http://msdn.microsoft.com/en-us/library/office/ff194819.aspx for details on the Workbooks.Open method.