The problem that HBR misses here is making the issue "about Ted" rather than "missing the deadline." If you can credibly talk about what was needed to make the deadline and wasn't there, then you can talk to the solution. Ted may come up to you in private and say "I'm not sure I can handle this" but they don't need to feel like a turd.
I once explained to a person that if I asked them to lift a car off the street would they consider themselves a failure for not being able to do it? or me unreasonable for asking it? They said it was an unreasonable ask. (which in that way it is) and then I asked "Ok, so if I said we need that car up and off the street, can you take care of that?", their response was "What tools can I use?" and I say "What do you need?", they say "A crane, a crane operator" and I say "Ok, the crane company will be in touch." Now they are going to achieve the same thing, "Get the car lifted off the street" but it's not about them, its about getting what is needed to be done, actually done.