That only works in a community property state. Otherwise, an MMLLC files Form 1065, unless they elect to be taxed as a corporation.
If not entered into with a profit motive, follow the Hobby Loss Rules.
How could $200,000+ ever be usual & necessary for revenue of $900, especially with NO profit motive?!
Did they actually run their hobby income and expenses through the LLC bank account or LLC charge card?
If they paid their hobby expenses personally and deposited their hobby income into their personal account, then you report their hobby income on Sch 1 line 8. Hobby expenses are NOT currently deductible until the sunset of the TCJA. (After the TCJA sunsets, if Congress doesn't change the law, hobby expenses will be deductible -- up to the amount of hobby income -- in the 2% miscellaneous section of Sch A.)