Though Forum Administer is correct, there is a slightly more nuanced answer.
First, I don't think haemophilia was sufficiently widespread at that time to warrant a significant charitable organisation, at least not as compared to major issues like war casualties, their families, major poverty, the major fatal or debilitating diseases, orphans, etc. The incidence of haemophilia was, and remains, quite low.
Also, in some cases, most notably with the Romanov Imperial couple and their haemophiliac son and heir to the Russian throne, Alexei, it was a very well-kept secret which the Emperor and Empress for their own reasons wished to keep. I couldn't say for certain but I think the same rationale applied to the British, German , and Spanish royal families.