Esan pleaded guilty to attempted murder in January, after the case had been delayed several times amid concerns over his mental health.
He had made several unsuccessful attempts to join the British Army in the years before his attack, with his first application in 2020.
That same year, he had been referred to mental health services as he appeared to be mentally unwell and reported hearing voices.
His mother believed he should not have been in the community due his mental state, the court was told.
Eileen, who sings in a military wives choir, said the couple welcomed Esan’s guilty plea.
“For us not having to relive the ordeal through a trial and subject poor jurors to our horrendous ordeal, there was a massive relief that he had, in our minds, done the right thing and pleaded guilty to his crimes,” she said.