Henry McGowan, 30, appeared at Portlaoise District Court on Thursday after the death of his father John McGowan, 66, at the Ballyfin Demesne hotel in Laois on Tuesday.
McGowan was charged with his murder and made no reply to the charge when he was cautioned by Garda, the Irish Police, according to The Irish Times.
The outlet reported that McGowan was remanded in custody inside Cloverhill Prison and the case was adjourned to November 18.
McGowan's lawyer Barry Fitzgerald said he suffers from significant mental health difficulties.
Garda sources told Extra.ie that Henry had arrived at the hotel several days before the death after a trip around mainland Europe.
The outlet reported that he soon started acting erratically at the hotel and staff then alerted his father who was in the US at the time.
The judge presiding over the case has allowed McGowan to receive immediate medical assistance relating to his mental health.