Bluebell, I'm so sorry - but your father sounds wonderful the way he's taken the news so calmly and insisted on you ahving your holiday. He sounds a lovely man and obviously cares a lot about you.
You are quite right to go for the spa and the break - you need to be strong and well to support him - and if he is worrying about you, that won't help his recovery.

Will be thinking of him in my prayers.