I think the idea of "following your dreams" is incredibly oversold to people, especially the young, but reading this it seems like this particular guy's problem wasn't that he followed his dreams, but rather that he followed his dreams while recklessly failing to do any sort of planning at all.

Of course you cannot easily collect unemployment if you resign (though he eventually did via suing, which despite my leftist leanings rubs me the wrong way). Of course finding an entry level position in a new field in which you have no experience and little to show in the way of a portfolio is going to be rough at 42.

If you really, really want to follow you dreams, go for it, but don't be an idiot about it. Research what you want to do and then do what you want to do while keeping the old day job going. While there are some careers where this isn't an option (eg. being a doctor, which is obviously going to require a huge educational commitment), there's no reason that I see why this guy couldn't have attempted to get into advertising this way. If working essentially two jobs is really not an option for some reason, live cheaply and save enough to last you 6 months to a year, and then follow your dream. If it really is your dreams. If what you are jumping off into is really your dream career then surely it can wait a bit and is worth living frugally for a while.