Help death in bfs family

<3
My boyfriends sister has just died in the last few hrs and he lives an hr away. Managed to rope my dad into helping me pick him up and on way now. 
Not sure how to console him or his family only been together 1yr6m not sure if they'd want me around but he says they love me etc so I might stay and console him and help tidy and make tea. Any advice ? Thanks.