- We all are doing fine here and wish the same to u all.Well,my health is good and everything is normal.
You could also say 'and hope you are all well,too', which is the kind of thing we might say in British English. I don'tknow if it sounds OK in American English.
- He is taking off from tomorrow,but we are not going to NewYork and have learnt that she is visiting Chicago this week.
Taking off- I'm not sure about this- maybe use 'leaving', as the departucre seems more important.
- Last weekend, he was down with lower Jaw tooth pain and suffered a lot (this should be two separate words),now he is doing fine.Actually, we were invited to his colleague's daughter's b'day, but
because of his tooth pain, we couldn't attend that ('the' ounds better to me than 'that') party.
Maybe it owuld be better to say 'a colleague of his' as the way you have put it, it sounds as if he only has one colleague. If this is the case, then leave it.