You can deactivate the Help button capability by modifying m_psh in the property sheet object as follows:
mySheet.m_psh.dwFlags &= ~(PSH_HASHELP);
You can activate the Help button again with the following:
mySheet.m_psh.dwFlags |= PSH_HASHELP;
The m_psh variable is of type PROPSHEETPAGE. The dwFlags field of m_psh determines if the Help button of the property sheet (the parent of the property page) is enabled or disabled.