Then he went home; and the crowd came together again, so that they could not even eat. When his family heard it, they went out to restrain him, for people were saying, ‘He has gone out of his mind.’ (Mark 3: 20-21)

In many languages - and certainly in koine Greek - pronouns are often implied. It can be a bit like Abbott and Costello's routine of "Woo's on first?" Who is acting on whom?

The first verse above can be reasonably understood as, "Then going to a dwelling place; the crowd gathered again, so that they (Jesus and his followers?) could not eat."

In the next verse the use of family is speculative. A very literal translation of the Greek could read: "Hearing this they went to exert power saying it is amazing." The implied pronoun could be the disciples seeking to influence the crowd, rather than family trying to constrain Jesus.

What is translated above as "out of his mind" can also mean to amaze, astonish, or throw into wonderment. Which meaning is best depends mostly on point-of-view.

In these particular verses there is no way to know for sure. There is not, in my judgment, even a contextual clue as to a more likely meaning. There are aspects of scripture that we can only approach with love, humility, and good humor.

The possibility of confused pronouns in these verses may have been first suggested by Johann Christian Schottgen (1687-1782) who translated and published A New Lexicon of Greek-Latin in the New Testament in 1765.