climbing and jumping

I’m not sure if anyone else has this problem or not. A friend of mine, who shall remain nameless, insists on never using any sort of ladder or even a chair to reach a high place. Instead, he has the bizarre habit of climbing – or in some cases, jumping – to access hard-to-reach spots. When I or others suggest (in a friendly way of course) that he use a chair or stool, he defensively insists he is “mature enough” to make his own decisions.
For example, even when doing things like changing a light bulb, a task which everyone will gladly reach for a stepstool to easily twist out and replace the old bulb, this friend insists on a strange practice of simultaneously jumping and unscrewing the bulb. Needless to say, some bulbs have been broken by my friend while performing this weird procedure.
Things came to a head recently when a letter fell off a plaque. My friend, upon noticing the fallen letter, bolted across the room and actually climbed on to a ledge in what turned out to be an unsuccessful attempt to reaffix the letter (there was chair right there which he could have used).
Someone made a remark along the lines of “Those letters really should be more secure.”
My friend, apparently mishearing the sentence, protested loudly that he was, indeed, very mature, and stormed out of the room. He was later heard threatening that he will take the issue to a public forum of some sort.
Any suggestions on how to deal with this situation?