In all honesty there are a few things that I have learned about communicating with people who are in a palliative care setting, the first is don't be uncomfortable around them, it makes everything worse. Just be yourself, talk to them, make jokes (not about the cancer of course) but don't treat someone different because they are dying. I know that this may sound dark but people will open up more if they are comfortable.
If you are really concerned about how to talk to someone with cancer - there are resources that you can access.
http://www.albertahealthservices.ca/...af&rid=1074214
In Calgary should be able to help.