Lets assume that he gets around to giving each event a real honest shot. I think best case scenario he misses out on the steeple and marathon. The steeple is just such a technical event and would take time to really nail it (yes, I know he's done it before, but its been 7 years since he last raced it). The marathon I think requires a bigger shift in training than he will be able to manage.
The bigger issue here though is that he doesn't have enough time to get them all. Having lost the 1500m in Paris, I expect he'll be giving it another shot in LA 4 years from now. I don't know if his ego will allow him to move on from that event until he has gold in hand, regardless of whether he snags the WR before then.
So that precludes him from making any real attempts at any events over 5K until 2029 at the absolute earliest. At that point he'll be 28 give or take, and (assuming he's gotten 1500m through 5000m) he will still have the 10K, HM, and marathon left. Races that are conducive to WR attempts (conditions, timing, competition) don't happen often, not necessarily even every year. So I think its unlikely he's able to line up each event within those constraints.
Also, while age is less of an issue for 10K and up, the longevity of his brothers (or lack thereof) don't bode well for his ability to keep training at a high enough level to get WRs in those longer events.
This isn't to say he's not capable of getting all of them, I think he absolutely is (barring the steeple and marathon maybe). So he's not necessarily delusional. But I think from a practical standpoint its just not likely.