Harassment or bullying?

I was sitting in the kitchen of the house that I share with my mother when my American sister-in-law, who was visiting, placed a mobile phone in front of me on the table. My American nephew, who is a young adult, was on a video call and I began to make small talk. I am 49 and live in Ireland.
Then I noticed that his facial expression was extremely hostile and aggressive and I couldn't speak anymore. He continued to glare at me without speaking. My sister in law picked up the phone after approximately fifteen seconds of this wordless video call.
A few days later my nephew arrived. Our first meeting occurred when I was sitting in the kitchen and noticed that someone was standing one foot in front of my feet. I looked up and my nephew's face and my sister-in-law's face were three or four inches apart. Their eyes were locked in a gaze completely excluding me. In order not to be intimidated I stood up to shake his hand and they left the room immediately.
Is this harassment or bullying? What can be done about it?