I am sorry. This will be a sad, difficult time but, for now, I would take a cue from your aunt and spend the time positively; renew good memories and have small, wonderful moments that you might not have had you no warning of her approaching death.
There will be time to grieve and you will always feel the loss but, it seems that she is looking for a few more good moments with those she loves. ((((hug)))). If you spend the time looking for a cure in this situation (as described) you will lose time that could be spent being with the person who is still alive.