I got your point, you are wondering why prescription for LD O- Calcium and Vitamin D is giveen to your father !! is that so ?
I have answer to your query. Actually the drug Warfarin
has some side effects, it causes bone density
reduction and sometimes leads to pathological or spontaneous fracture
and weakness of bones of body.
Thats why to prevent these effects, warfarin is now given with calcium and vitamin D both maintains proper calcium balance and prevent side effects.
hope my info helped you
Dr Hari Om Chandrakar