Any way to grab emails off an old NTFS disk?

This might question might not have a 'legal' answer but I'll ask it anyway. My dad is 15 year dead but I still have the disk out of his old Windows computer. It seems my sister want's me to try to dig up his old emails for a book she's writing. I have the disk mounted on my Linux machine with no trouble, but will it be possible to grab his emails? I suppose the disk had a PW but that's long gone tho I have a guess. Or is this the sort of thing only the CIA can do?