I just thought I would share some of my experience, as I remember feeling very alone and would have appreciated a community like this one.
My partner lost his mother to cancer when we were both at university. Throughout our second year at uni we would spend each weekend travelling back and forth to visit her, either in hospital, at home, or finally in a hospice. She passed away during our end of year exams - the uni forced my fiancé to sit an exam the day after his mother died. (Needless to say, he didn't pass it!)
My priority throughout her illness was always to be there for my partner as he struggled with depression throughout her illness and after her death. He wanted me by his side throughout and I know that helped him. It did at times make me worry that I was intruding on what should have been private family time. I was often unsure whether it was appropriate for me to be present - particularly towards the end at the hospice.
I often think that terminal illness has a huge ripple effect - the person with the illness is at the centre, and the effects spread out through their network like ripples on a pond. Although I was on the edge of this, I found I often felt very alone as I tried to support my partner and his family, and I in turn needed support.
For anyone experiencing anything similar, and trying to be strong for people they love - please know that it is OK to struggle and need support!