Helios actually makes the trader a limited member/partner of their trading firm. This means that at tax time, the trader receives a K1 statement where the trading PNL passes through with the normal benefits. For instance, on Futures, it's the 60/40 capital gains as normal. This sort of income is not normally subject to SE tax.
While Helios will issue you a K1 statement, they are not tax advisors, so please check with your CPA to ensure what is the specific situation for you.
Please note that Earn2Trade is not a tax advisory and present information does in no way constitute tax advice.