I would be interested in know how the IRS defines a "security". I would say there is still an argument that the IRS could consider bitcoin to be a security. They gave examples of securities as being stocks, bonds, treasuries. One thing I did not see was commodities like gold, and oil (which I would think would also fall under the wash sale rule - at least using logic).
Obviously he needs to work out the difference in gain rates, but without any specifics it's why he should seek advice as whether claim the losses this year or next. His "significant capital gains" are all relative, and may be wholly in the 0% rate for all we know.
I would personally not consider any capital gain that would keep my income low enough to still be able to pay 0% taxes on it to be "significant" but I do agree that every person's situation is different and this may be a possibility