Is it possible for all circuit breakers in a panel to trip in the same time (for one fault)?
I checked the panel by myself and all CB were closed. It was just a
  small issue and he just thought that they are all open.


I'm trying to interpret this - does he think CBs that are open (tripped) are actually closed (operational)?  Does he not know which direction is which?

I'm basing the following on my experiences with standard CBs in the US both residential and commercial buildings...

CBs often appear closed (operational) when they are in fact tripped - the handle barely moves.  One needs to cycle the CB to OFF then back to ON to get them to reset.  Is it possible he saw the tripped CB (from the washer) and thought that all the other CBs were also tripped because they looked similar?