Declan Donnelly served as a pallbearer at his brother's Mass on Thursday.
The I'm A Celebrity... Get Me Out Of Here! presenter helped carry his late sibling Fr Dermott Donnelly's coffin at the Catholic service at St Mary's Cathedral in Newcastle ahead of his burial on Friday.
A close friend of Dermott's recently revealed a suspected brain bleed was the cause of death.
Fr Peter Kyi Maung, who served with Dermott at St Joseph's Church in Stanley, Co. Durham, recently said: "He was hardly breathing in the bed, it was so sad.
"They think he had bleeding on the brain. Declan had come to be with him and their mum was there as well, I saw her at the hospital and it was so hard for her, a mother seeing her dying son.
"When she hugged me, I knew how much she was suffering."
Fr Dermott - who was ordained 30 years ago - was believed to have been carrying out community work when he complained about a headache and later collapsed.
He was rushed to North Durham hospital and Declan travelled from London to be with him.
However, his death was announced in a statement from the diocese of Hexham and Newcastle.
The statement said: "It is with great sadness that we have to inform you of the death of Fr Dermott Donnelly, who died peacefully this afternoon in hospital.
"This has come as a great shock to all of us. Please pray for the repose of his soul and keep his family, especially his mother, in your prayers at this difficult time."