Yes, Brazil should probably observe a national period of mourning. Some of their beloved soccer players have died. It is a matter of national pride and mourning and deserves a designated period to recognize the loss and allow people to process. It also shows the rest of the world the country's commitment to their team.
The nation should observe a national period of mourning. This is because this is a national crisis. The plane was carrying the Brazil's Chapecoense soccer team which is the national team. They were going to Colombia to represent the country. Therefore, having a national mourni9ng period will be enough to how them respect.
Brazil has suffered an enormous national shock after a plane crashed in Colombia killing seventy five of its citizens. After a national trauma such as this, it tends to be beneficial for the country to observe a period of mourning to help people collectively come to terms with what has happened.
There are tragedies that happen every single day around the world. People lose loved ones for natural reason and for unnatural reasons, every single day. It is terrible for the families of the people who are lost, and for the lost potential. But there should not be a day of mourning unless those lost are public officials or dignitaries.