My dad picks his nose and flicks it on the floor what can I do?

On a slightly different matter he also doesn't believe me when I speak the truth what can I do?

Rekon he thinks it is an ok thing to do, so just try and ignore it. Have seen this happen

Rekon he thinks it is an ok thing to do, so just try and ignore it. Have seen this happen

Yes he does think it's ok but it's unhygienic. Other people have to touch what he has touched and then we could eat food which becomes contaminated with his bodily fluids. And there is nothing I can do. My dad only said yesterday to my cousin that his first thought in a dispute is to use violence.