Yes.
He should probably file, but is not required to. He can still carry his losses forward without actually filing. But, he should file for two reasons:
1. The 1099-Bs from the sale could generate an IRS inquiry. It may be easier to file now than explain it later.
2. Although he can most likely carry the entire loss forward, if he has no other income, there are times when that's not exactly so. It's best to at least prepare a tax return to accurately calculate the capital loss carry forward. Actual filing of the return documents the loss further.
