21 Jesus asked the boy’s father, “How long has he been like this?”“From childhood,” he answered.

Read Mark 9:21 Using Other Translations

And he asked his father,How long is it ago since this came unto him? And he said, Of a child.
And Jesus asked his father, "How long has this been happening to him?" And he said, "From childhood.
“How long has this been happening?” Jesus asked the boy’s father. He replied, “Since he was a little boy.