Your relatives won't mind this expression either. Give them a red envelope and you can buy what you like!
Relatives are ill. Under normal circumstances, we should all bring some nutrition to visit them. This should be a courtesy, a sign of respect, and a wish for his early recovery. In layman's terms, it is human feelings.
However, since you are out of town, you can not visit, but you can't lose your manners. So personally, I think it's good for you to send him a red envelope to transfer money, because he's just sick and shouldn't be so particular.