Timmy Helmet only available for a limited time?

This might not be true, but my brother watched some videos that claimed the Timmy Helmet would only be available until March 2018. Is this true? If so, then I better go nuts in the custom games…

No, there is no end date for the Timmy helmet.

There was originally a cutoff date, but after some troubles with the distribution they decided to remove it like Stckr said.