The phrase "if anything happens to someone" is often used to express concern for a person's wellbeing and to make sure that they are taken care of. However, there are many other ways to convey this sentiment using different words and phrases.
Some synonyms for "if anything happens to someone" include "should anything go wrong," "in case of an emergency," "if there is any trouble," or simply "if anything occurs." These alternate phrases can be used interchangeably to express similar levels of concern for a person's safety and wellbeing, and can add variety to your vocabulary when expressing sympathy or concern in different situations.