Well, tricky. If this was a "hobby" then no, but the IRS will probably send you a letter asking you to explain.
If this was part of "an ongoing trade or business" then yes, he needs to file. He will owe 15% self employment tax but does not make enough to pay income tax. You will want to use the Free File Alliance version, which is for qualifying low income taxpayers and includes all forms that are normally in the paid version. For IRS regulations, this is a separate web site and you will need to create a separate login account for his return https://turbotax.intuit.com/taxfreedom/
An "ongoing trade or business" is any activity that you regularly engage in with the purpose of making a profit. If he is a regular actor (school, local amateur theatre, etc.) and this is his first paying job, then he is probably engaged in an ongoing trade or business as an actor. If this is a one-off, he is not a regular actor (even unpaid) and not likely to happen again, then you might get away with claiming it as a hobby. As hobby income, you would not file anything now, but the IRS may send a letter to him asking him to file, and he would have to answer by explaining the reasons that he is calling it hobby income.
