There is no proper time, and everyone handles grief very differently.
Some will become very withdrawn and shun company, not able to face people.
Others cannot bear to be alone and try to keep busy and sociable for fear of going insane if they don't.
Others are very stoic,and try to keep going as usual - the stiff upper lip, but you don't know how they are truly feeling.
Still others go through an extreme range of the above over a period of time as they try to 'get over' bereavement.
There is no proper way to grieve nor a proper length of time. Nobody ever knows how another is truly feeling