There is a great tradition in Ireland of sending sick children away to places to reinforce fantasies proportional in absurdity to the seriousness of their illness.
For terminally ill children, Fatima, Lourdes, or other similar places of unmitigated religious daftness, are often locations of choice; for seriously ill children, particularly those with leukemia, a Christmas trip to Lapland is often considered the appropriate place of call.
Profound question: where would Santa go if he got leukemia?
Insensitive suggestion: tell all the kids with leukemia that Santa got leukemia and probably will be getting chemo at Christmas so won’t be able to deliver presents. But say it in the tone of voice that really means that you don’t expect him to be alive by Christmas. While molesting them.