A man has been accused on Thursday of murdering his 100-year-old grandmother with an axe as she sat in a wheelchair. He went on a trial in the northern German city of Hamburg on a charge of homicide. “He could not cope with looking after her,’’ the prosecuting lawyer told the court. The prosecuting lawyer described how the accused, a 37-year-old German born in Estonia, attacked the woman in her Hamburg home in the early hours of March 6. The woman, who suffered from dementia, received at least 16 blows to her head and neck as she attempted to defend herself.