Yeah that's the narrative from Cerulli but I think he's got the chronology wrong, the death of the Imam at Ceel Cawl seems to have taken place much earlier than the invasion of Mogadishu, a century or more.
There are two oral histories from the Hiraab oral tradition, the story of the death of the Imam of Ajuuraan at Ceel Cawl, and the story of the takeover of Mogadishu. Cerulli puts the Imam's death later in his chronology and the Mogadishu takeover earlier, but abtirsi tells a different story.
Based on theoretical abtirsi dates?