When is a good day just a good day?

My family's had couple of nice and positive days, even though that still includes our special way of sarcastic/cynical/sometimes barking communication and attitude towards life. Kind of hard to explain better, I suppose one either knows the feeling or doesn't.

Anyway, in this happy family world I wouldn't be myself if I wouldn't worry ... We're far from a perfect happy family, I could still kick my sister's ass every day for some reason or another and I can't stand seeing the kid wasting all this time either on computer or in front of TV! My mom, that's a whole another story as I'm never sure if she'll accept my jokes or get offended by it. On the other hand my relationship with dad is nearly rock steady at the moment (knocking on the wood...). The two of us have had some pretty rough times of not talking/hating each other for months and even years. It's a great step forward that we can talk, even when it means that we fight. Rarely any discussion is finished in mutual agreement on a matter, we're both too stubborn and always too proud to admit a mistake. But we TALK. I say something, he listens. He says something, I listen.

Well, not always, to be completely honest. It's still a daughter-daddy relationship :)

So the thing that worries me is how do I know if he's genuinely in a good mood or if it is already the peak of current enthusiasm before the deep fall back into the regular mood? It's so unusual to be able to converse with him and see him in good spirits, even though I can't really differ any more if's it's because he's had some spirits or is it the real feeling ... And then when he's in a really good mood it just confuses me more! Sure, I wouldn't have problems with this if his general health condition would be ok and not one of an alcoholic ...

The other night the whole family went out together, I'd say it's been lots of months if not years since this last happened. It this then that I saw how we were a really happy family, 2 boys and 3 girls, who love to dance  and ruled the dancefloor. I'm not exaggerating, we do look our best when we dance all together :) Anyhow,  dad of course danced with all of us girls, and that's when this unnecessary thought came to my mind and got stuck there since.

How much can he take? What if his body can't work with all this sudden activity and excitement?

Is there an answer to that, that I could find somewhere?