Although once heir to the earldom of Carrick, Cailean appears to have died before 1250 (the year of his father's death).
The traditional view, going back to the 19th century, is that Donnchadh's son and heir was Niall.
[2] According to this argument, Donnchadh's son and intended heir was Cailean (alias Nicholaus of Carrick), who as his son and heir, issued a charter in Donnchadh's lifetime, but seemingly predeceased him.
[2] Cailean appears to have had a daughter, Afraig, who married Gilleasbaig of Menstrie, a Clackmannanshire baron who was the first attested man to bear the surname "Campbell".
With this lady, Gilleasbaig fathered Cailean Mór, the ancestor of the later Earls of Argyll.