I do not know if it is connected at all, but there was a John Adair, nephew of Ann Maxwell of Ennisbrogue, co. Down, c.1774 mentioned in her will.These Maxwells may have been connected to the Clanbrassill in another document found on the same page at :
Ann Maxwell was the sister of Rev. William Maxwell and Sarah Waring (nee Maxwell ?) of Drogheda.
Have an idea that these perhaps may be related to the James Adair, recorder of London lineage.They descended from way back, I think from the 2nd son of Ninian. Perhaps connected to the Wilson and Small families of London.