http://www.tmz.com/2018/06/07/sons-of-anarchy-star-alan-oneill-dead-47/

The Irish actor appeared in seven episodes of the FX series as Hugh (http://sonsofanarchy.wikia.com/wiki/Hugh), a member of the True IRA. A cause of death has yet to be revealed.

Sons of Anarchy's Alan O'Neill died from a drunken fall (http://www.tmz.com/2018/07/27/sons-of-anarchy-actor-alan-oneill-cause-of-death-alcohol-fall/)
The Irish actor, who played the former True IRA member Hugh on the FX series, died last month of chronic alcohol overconsumption, blunt force head trauma and heart disease, according to the L.A. County Coroner's office.

Sons of Anarchy's Alan O'Neill died from a drunken fall (http://www.tmz.com/2018/07/27/sons-of-anarchy-actor-alan-oneill-cause-of-death-alcohol-fall/)
The Irish actor, who played the former True IRA member Hugh on the FX series, died last month of chronic alcohol overconsumption, blunt force head trauma and heart disease, according to the L.A. County Coroner's office.
I didn't know him but maybe he had too high expectations of himself in the precarious world of acting, alone in a foreign country, seeking solace through soft drugs and alcohol and with no regular doctor to turn to unawares he was spiralling out of control.