My father is waiting on the results of a multi disciplinary team meeting to decide whether or not to treat his pancreatic cancer. They should decide on Monday.

My 9 month old was at a party yesterday where another child showed up covered in pox. It was her 2nd day of spots. I left as soon as I realised, which was after about 15-30mins after she arrived. We were outside. 

Can I go and see my father with her tomorrow, as planned, or should I cancel? 

A lot of mutual friends were at the party with their children, do I have to avoid all of them for 3 weeks?

Thanks in advance for any help you can offer. The thought of not seeing my dad for 3 weeks is heartbreaking, but I dont want to make him sick or compromise his treatment.