Depending on the Regions there are various Tradition . I am from Rajasthan so I am telling you about the tradition we follow and Now in Hinduism we are not allowed to Make the festival's on large scale if there is a death in home for 1st year. You can't celebrate festival on large scale but you can celebrate the festival on small scale. Like in Holy you can celebrate this but within a limit you can go out color your relatives but in a limit.You can Celebrate with your relative or close ones. you can go to your relatives home or homes of people close to your family. You shouldn't celebrate with all person for eg. Neibours ,friends , colleagues you should celebrate with few one only relatives and person close to you .You had to celebrate first festival with your whole Family You had to Celebrate festival with your whole family for eg. If a person has three son and two daughters after his death the whole family of his three sons had to celebrate the festival at the home of their father or where their father was living and for daughters they can come alone or they can come with husband to their Father's home to celebrate the festival after 1st festival you can Celebrate other separately or if you want to do it jointly you can do it .
In many region of India or In many castes you can't Celebrate the 1st festival because there is a sorrow in the family because of death , To express the sorrow of death and due to the cultural rules you aren't allow to celebrate. That's why in many regions people are not allowed to Celebrate festival for the First year or the first festival after the death