Sure. As for a saint, you can pick any saint you wish. You might look at your friend’s life circumstances and choose a saint who has a particular interest or patronage in those areas (e.g., St. Joseph for a husband and father, St. Thomas Aquinas for a teacher). Some “all-purpose” saints for conversions might be St. Monica, mother of St. Augustine; and St. Jude and St. Rita of Cascia, patrons of impossible causes.
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