How would you judge his behavior...?

My friend Alen and his older brother Eric came to visit me at the hospital today. Well, we just talked for a while until they had to go. Alen was very quiet only looking and smiling at me.. like he was glad to see me. Alen’s older brother Eric said to me: “I don’t know if you feel like giving a hug, but…” and almost put his arms around me, when out of nowhere a loud “EH!” came from Alen and was directed at his brother. He sounded so mad and I saw him give Eric a mad look. How would you percieve this? I felt fine today until Alen shocked me with that angry scream. I didn’t let him see that he upset me, but I was actually scared. After Alen looked at Eric, they just left. Alen seemed upset and mad and ignored me, while Eric was polite and happy and just said “bye” with a smile. Anyway… suggestions?