Stepson hurt her bad...HELP PLEASE?

Okay my boyfriends mom has cancer and today was her 37th birthday. When we was there her stepson decided to make a film of her life, he made fun of how she looked with cancer and showed everybody (at least 30people) now she's been in her room all day. At first i thought it was messed up but didn't say nothing but when my boyfriend told me his mom has it again(throat cancer) i feel horrible. I know i didn't do anything but to think that is so bad. Everything was happy at the party and everybody was celebrating (we even told them we were going to move in together which made it better). So i guess my real question is how do we make her feel better? People have tried talking to her and i tried bringing her cake and stuff but she looks really sad(like you can see how she's been crying) so help please