FIL Has Pneumonia - Contagious?

My FIL has pneumonia and is hospitalized currently and being treated for low oxygen among other pneumonia related symptoms.

Our nephew recently was diagnosed with the flu and that turned into pneumonia. I know my FIL has been around our nephew.

My FIL also babysat my kids two days ago. Are my kids at risk?

Here’s more information. Should I be worried?

-FIL tested negative for the flu

-FIL did not have a fever at all

-When my Nephew was around him, he had been fever free and on antibiotics for 48 hours

-FIL has had a chronic cough for months and has severe asthma