In the novel After the Funeral, Timothy Abernethie is the fourth child of Cornelius Abernethie and younger brother of Richard Abernethie. After the death of Richard, Timothy became the last remaining male sibling of his generation carrying the Abernethie name. Timothy is married to Maude. The couple had no children and lived at Stansfield Grange in Yorkshire.
Timothy was an invalid and a recluse. His ill-health prevented him from attending Richard's funeral and so was not present when Richard's will was read. Although the will left him a fair share of the estate, Timothy told the family solicitor Mr Entwhistle that as the eldest surviving Abernethie, Richard ought to have left everything to him and trusted him to look after the rest of the family. Timothy said that Richard had hinted as much to him, although privately, Entwhistle was sceptical. Entwhistle understood, among other things, that running the Grange was expensive and Timothy and Maude were short of money. Timothy's obsession with money was demonstrated again when his sister Cora Lansquenet died. He was upset again when Cora's will left her estate to their niece Susan Banks. Surely as her brother and next-of-kin, the estate should have been left to him. Moreover, Cora's share of Richard's estate would now be split among the rest, why shouldn't it go to him as next of kin? Nonetheless, despite Timothy's ill-feeling to Richard, Poirot did not consider him a plausible suspect in the deaths of either Richard or Cora.
Except for Maude who was entirely loyal to Timothy, the rest of the family were not entirely taken in by Timothy's constant state of ill-health. They suspected being an invalid was more of a hobby than anything else. George Crossfield, for example, baited him by pretending to want a Spode dessert service which Timothy also wanted. The dispute over who should get it almost drove Timothy to a fit but George thoroughly enjoyed the event, believing the old man to be nothing more than a crock and a hypochondriac.
Timothy Abernethie is played by Benjamin Whitrow in the film adaptation of the book in ITV's Agatha Christie's Poirot series. Like in the novel, he is an invalid and wheelchair-bound although Poirot showed later that he was much fitter than he pretended to me. Timothy's role is slightly different and he is involved in a sideplot that is unique to the adaptation.
In this case, Timothy did not expect anything from Richard's will as they had a falling out some years before. In order to slow down the disposition of the estate, he absented himself from the funeral and used the occasion to break into the Entwhistle's office to steal the deeds to Enderby Hall. As a result, the estate could not be sold and the proceeds distributed to the beneficiaries. He was therefore surprised to learn, at the reading of the will, that he was getting a share of the estate. He then had to contrive a way to return the deeds to Entwhistle without being caught.