Hi there ... I'm so so sorry your going through this heartbraking time at the moment.... but know your not alone ... I've just lost my beautiful niece to terminal lung cancer.... she had 5 kids who went through similar feelings of helplessness as your feeling right now ... 

All I can say is each one just sat with her, and held her hand ... they walked that last long journey with her .. there's no easy way through ... it's o.k to admit you all feel scared .. but in the time you have, tell him everything in your heart .. how much he's meant to you ... he helped you walk, and watch you through life, now it's time to help him ... 

It's a long hard sad path .. esp at such a young age .. I'm sure your trying to be strong for everyone .. but you need an arm round you to ... and even though you are loosing his presents... you can keep him safe in your heart ... where he can come along and see through your eyes ... I'm sure I've had my mum look out for me, and send me signs she's still around ...

My nieces kids are holding on to each other now .. they remember the laughter and good times, as well as share tears and thoughts ... we never stop missing them ... but we do learn over time to adjust... sending you a vertual hug.. Chrissie x x