Liam Adams, the brother of the former Sinn Féin president Gerry Adams, has died in custody while serving a 16-year sentence for raping his own daughter.

The 63-year-old had cancer and was moved from Maghaberry prison to a hospice in Belfast this month.

The Northern Ireland Prison Service said he died on Monday morning and his next of kin had been informed.

The former IRA member was convicted in 2013 for raping and sexually assaulting his daughter Áine between 1977 and 1983 when she was aged between four and nine.

The case piled pressure on Gerry Adams to explain why he did not alert authorities when he learned of the abuse in 1987.

Liam Adams admitted the abuse to his brother in 2000 and went on to work in youth clubs, including one in west Belfast, the constituency of Gerry Adams, who was then an MP.

Gerry Adams. Photograph: PA

Áine said the politician brushed off her request to keep her father away from children. “Gerry told me that was Liam’s way of trying to make up to the community for what he done to me.”

The Sinn Féin leader gave his first statement to the Police Service of Northern Ireland about the abuse in 2007.

When the case led to a subsequent prosecution and public outcry, the Sinn Féin leader accused political opponents of exploiting a family tragedy and said child abuse was “above politics”.

Sinn Féin and the IRA have faced additional criticism in a separate case involving Maria Cahill, who said she was repeatedly raped by a senior IRA member and that the republican movement covered it up.

Adams, who stepped down as Sinn Féin’s leader last year, made no immediate comment on Monday. He reportedly visited his brother at the hospice this month.

After a lengthy attempt to avoid extradition from the Republic of Ireland, Liam Adams, a former Sinn Féin activist from west Belfast, was found guilty in Belfast crown court of 10 offences against his daughter.

Now called Aine Dahlstrom and aged 45, she waived her anonymity to highlight the case.

Gerry Adams disclosed in 2009 that his father, Gerry Adams Sr, had “emotionally, physically and sexually” abused members of their family.