It is possible you are thinking of:
* John Hall (1575-1635): He was a physician and Shakespeare's son-in-law, married to Susanna Shakespeare. He might have held some opinions on Shakespeare's work, but no concrete evidence suggests he was a vocal admirer or critic.
* John Heminges (1561-1630): One of Shakespeare's close friends and fellow actors. He was also a shareholder in the Globe Theatre and a key figure in the First Folio, the first collected edition of Shakespeare's plays. Heminges likely held Shakespeare in high esteem, as he dedicated significant time and resources to preserving his friend's work.
If you can provide more context or information about "John Holbrook," I might be able to give you a more specific answer.