Check with the hospital, about if there are any "support groups".... support groups can be very helpful and a place to commiserate... for terminally/seriously ill patients and/or their families.
People who are ill, often feel that no one can 'relate' to them... since it is such a unique situation... and very emotional.
Having other similar people to talk to, in a support group, can then be very therapeutic for them.
As for you personally, offer to help them with errands/babysitting, cooking, anything that they may be too tired to do or unable to do, themselves, given their situation.
Sometimes, just being there for them... even if not actually doing anything, can help a great deal. My Dad was ill for a long time, and just having me be company for him, was something he really enjoyed. One thing my Dad did not 'like' was other people telling/lecturing him about how he 'should' feel.... because ultimately, an ill person needs to vent too and just have someone to listen... a shoulder to lean on and an ear to bend to 'hear' them.. .and all of their worries too.
Each person is different with different 'needs' when ill. Maybe, just ask them, how you can help. They may not even know themselves... since they themselves are trying to process everything too, emotionally and intellectually.
all the best,
Susan