I only read the OP not the article so I don't know if some hoax is going on but...Sad. African Greys are the one parrot who often actually DO communicate in what are considered to be complex sentences. See the abused parrot named Alex's story, Kept captive by a "reseacher". It's quite famous. VERY intelligent parrots. IQ of a toddler, they say.
She had a little scam going on (IMO) to get funding that she could use the bird to cure/address autism.
He was wild caught not captive bred with weak genes or "hand fed" so his wild genes were special. The researcher got him at a pet shop and for the rest of his sad life he had to live in a research facility doing experiments and tricks.
IE teaching him the difference between metal, wood, rubber and plastic ....then later he can tell you if totally different objects are that same material.
If you gave him a metal object he never saw before, he still knew it was metal.
He used to beg the researcher "I already did that" but she'd laugh him off and make him keep "working". You can see a video on Good Morning America when they kept trying to force his roommate Grey to perform and the bird didn't want to and got stressed and Alex got freaked out and started plucking his own feathers out.
So YES the bird is repeating something significant to him. But that's probably the extent of what they'll get from him.
Poor guy. These birds bond for life if possible so if he was bonded to a person who died it's going to be tough for the bird. There's a chance he can bond with a female Grey but often they have no skills left for their own species from having their brains screwed up by being "mated" to a human. Which is the point of "hand feeding" a baby. Trick the mind to think they are the same species as the stupid human feeding them, THEN refusing to allow them to be around other birds for relationships.
Having owned a pet store including parrots and boarding many client's parrots I can guarantee you sometimes they tell you what they "want" but an African Grey will very often be shockingly legit and precise. For quick example, it was not anything unusual at all to see in my store things like one boarder loved one employee of mine (common) and would argue with me that he wanted that guy not me. Like if I wanted to take him out of his cage or bathe him or even feed him....NOPE: "Where is Bobby?" "NO I want Bobby." Then the guy would walk in the door and the Grey would say "There's Bobby". "Bobby come get [bird's name]" and other "CONVERSATIONS". It was like you were talking to a toddler.
He had his own voice. When he wanted to mimic something, he would do it effortlessly but when he wanted to communicate, he used HIS voice. They all do, actually. But a Grey is something at on entirely different level.
If you were mean and put the bird in the room with the murderer he very possibly would give you behaviors that would make you believe it but you couldn't use it LOL