will this bad luck ever turn around?

my boyfriend was diagnosed with lukemia last year. his mom died of lung cancer four years ago when he was fourteen and his dad also has lung cancer. fourtuantly his dad and him were in a remission but yesturday he found out his dads cancer has come back in the fourth stage and has also spread to his liver. my boyfriend has been a mess and i can see no reason to blame him. his mom already died, his dad is dying, and there is a good chance that one day his cancer will come back too. i couldnt imagine having to live without my parents. and i cant even imagine what hes going through. i try to tell him to be optimstic and let him know im here for him but i feel its just not enough. i wish there was something i could do... but i dont know... i guess there really isnt anything i can do except offer my support and be a shoulder to cry on... i have no clue... his sister is the only one in their family who hasnt gotten cancer and i cant imagine how she feels either. its so horrible. i dont know what to do. i love this family as much as i love my own. and i dont know how to talk about it to my boyfriend. im afraid i'll say the wrong thing or that i wont be able to help him get through this... what can i do? how can i talk to him about this?