Just found out that my boyfriends grammas cancer spread to her lungs?

My boyfriends gramma has been fighting cancer for about a year and today we found out that it had spread to her lymph nodes and lungs. I work in the cancer research field so I know how bad it is and that she probably won't live ped this weekend. I know I need to be strong for my boyfriend because they were very close but I'm a pretty emotional person. I don't know if me going with him would help or make it worse. How can I be there for him without bursting into tears myself? I'm really not good at this stuff at all