Could Reduction In Platelet Count Be Due To Warfarin?

My dad is 77 and I am looking at his recent blood test results. Everything looks within range but his PLT is 104 and the range was 140-375. I looked it up and see it is platelets. He takes warfarin which is why takes these blood tests regularly. But I don't know if platelets are affected by warfarin. Should I push him to ask the doctor more about this? What is the effect on his day to day health? Symptoms? I live far away so want to make sure I know what to ask him. Thanks!