To set the ignore upper case to true, you could use the following:
hApplication := OLE2.CREATE_OBJ('Word.Application');
hOptions := OLE2.GET_OBJ_PROPERTY(hApplication, 'Options');
OLE2.SET_PROPERTY(hOptions, 'IgnoreUppercase', TRUE);
To actually toggle the setting, try this:
OLE2.SET_PROPERTY(hOptions, 'IgnoreUppercase', NOT OLE2.GET_BOOL_PROPERTY(hOptions, 'IgnoreUppercase'));