Have you or your father had any success with this?
My dad is still on Warfarin and still has the huge blood clot, it's not gotten any smaller :( and its not recommended to take Nattokinase while on Warfarin.
He is instead taking Serrapeptase which is supposedly ok to take while on Warfarin.
This will hopefully eat the blood clot and then he can come off Warfarin, start taking natural blood thinners and also take Nattokinase and/or start urine therapy since that seems the best way to rid oneself of blood clots. All clotbusting drugs that are used contain components of urine, so why not use one's own perfect medicine ;)