These are the articles I got my info from. Both these papers are mainstream publications with a good journalistic track record (edit: you're Dutch, right? Just clarifying for other board dwellers):

https://www.volkskrant.nl/nieuws-achtergrond/jongen-16-uit-breda-aan-beademing-door-corona-dit-virus-is-geen-grap~bca93e1a/

https://www.volkskrant.nl/nieuws-achtergrond/brabantse-artsen-substantieel-deel-coronapatienten-op-ic-is-onder-de-50~b6aff849/

https://www.nrc.nl/nieuws/2020/03/16/helft-patienten-intensive-care-is-jonger-dan-50-a3993863

Amphia's social media statements are very vague, it only mentions a "fake message" without specifying its contents. People on Twitter are asking for clarification, but get referred to an other non-specific statement on their website.

If those articles are based on fake news, somebody's probably getting fired, lol.

If you have more concrete information on why this is fake news, I'd love to hear it.