A former teacher would have been "totally devastated" at being involved in a crash which killed two Cumbria pupils, his widow told an inquest.
Patrick Short, 68, died along with Chloe Walker, 16 and Kieran Goulding, 15, when his car hit their school bus near Keswick last May.
Mr Short suffered from Type 2 diabetes, but tests showed this was "highly unlikely" to have played a part.
Wendy Scott, 71, said he was a "very principled and responsible" man.
A number of other Keswick School pupils were injured in the crash, which happened on the A66 as the pupils were being taken home on 24 May last year.
The 49-seat coach and Mr Short's Honda Civic were travelling in opposite directions, the inquest at Cleator Moor was told.
Coach driver David Radcliffe said there had been no way he could have avoided a head-on crash with Mr Short's car.
All three victims died instantly.
Post-mortem examinations showed Chloe, of Frizington, suffered a fatal head injury and both Kieran, of Whitehaven, and Mr Short, of Braithwaite, died from multiple injuries.
Mr Short's widow said he had worked for Barnardo's in Maryport, was previously a "talented" PE teacher and was an active member of the local community in his roles as parish councillor.
She said: "He worked all his life for children. He said the last job he had was the best he ever had.
"I would describe him as a very principled man and a very responsible individual."
She said he was "always very careful and conscientious" with his diabetes medication and had not suffered any notable ill-effects since he was diagnosed in 2008.
Earlier a statement from Mr Short's Barnardo's colleague Linda Hodgson said: "He [Mr Short] would be horrified that he thought he may have killed a child.
"He had a real social conscience. He always did his best for this area."
The inquest is scheduled to last up to three days.