I Need Some Answers.....

Wonderfully busy weekend. Today I have a few questions that I'd love your honest opinion on. No holds bar. You will not hurt my feelings.
Three days ago Eli went home with his Nana for a few days. Yesterday Nana confirmed how wonderful he acts there. Plays well. Sleeps decent hours. A real joy to be with.
Here it was much the same. We all slept late and were in bed at decent times which never happens when Eli is here. It was peaceful. No fighting, no arguing, no fits of rage. I love my Eli, but I will not lie......it was a very peaceful couple of days for all of us.
This evening Eli returned and the atmosphere changed like night and day. Fighting, fussing......even a chair flew across the room. My question is why? If he can act good at others homes why can't he act that way here. if he can get along with his older and younger cousin at Nana's house, why can't he get along with his siblings here? Am I doing something wrong? Am I making his fits worse? Am I the reason his skin seems to crawl? At this moment I don't understand why being here is so tragic. I really thought the time away from everyone would do him so good but it seems he came home with more hate then ever before for me and his brothers.
Suggestions.......please.