My sons losing their nana

[phishing4cake]

I dont know what to do my oldest son and his nana are super close, he is 5yrs old. When my grama died last year i sat him down and told him she had been sick and that she was old, so she had died. I then took him to the wake, brought him up to the casket and explained it again. He knows she is dead, he doesnt ask to see her and when i mention her he reminds me that she is in heaven. I want to approach this in the same way. I was 7 when my mother died, and in a 15yr span after i lost several more immediate family so i have always been around death. I think its important to not hide them from it because its a part of life. The delemia im having is his nana didnt want him at my gramas wake and was mad when she found out later, i know she wouldnt want him there but i think its gonna make a big diffrence to him to know that she is not going to come back. His father thinks that i should only tell him something when he asks, but im afraid he will be looking for her and it will end up hurting him more in the long run. Im also afraid of my plan of action back firing in my face and him going to the casket and freaking out. AHHHH  i hate this. I dont want him to hate me later on for hiding it. Should i do what i feel is best, even if it means taking him there without anyone knowing or should i just risk it and hope he will be okay...idk