Thuldai, I am sorry to hear about your loss.

Is following the old rituals is what you really want to do? Since you don't know about, probably you don't pay whole lot of attention to it in the past.

I hope you don't take it in negative way. You will not be able to do the book way how they do in Nepal also. There are other ways to mourn. How about taking some time off and reflect on what he meant to you, his role to you.