A woman was lying in hospital. A man sent her flowers and a card on which he wrote: Get well soon. H.T.

The woman had a concussion so she said she didn't know the man (but of course she knew him).

She said to the nurse who read for her the message from the card:

Well, that is very kind of. him, - she said, visualizing an old gentleman whose private charity was sending flowers to patients in hospitals where they were unknown. ‘Very kind indeed.’

Does "private" here mean "personal" or maybe "secret"?

Does it mean that patients who lie in hospitals are unknown in these hospitals?
Using personal money to do nice things for others, including people who did not know him and whom he did not know.
OK. Thanks for this answer.