It sounds better if you refer to it as a home based business rather than a job. That way you can always blame the trader, and as owner of the business you can replace him with a better one.
That's your idea. We all have different ideas. Different aptitudes. Different "edges." Sometimes similar, but always different.
You can blame your troubles on either management or labor, depending on which hat you're wearing at the time.
Or you could put yourself on probation, have to explain every trade to the boss. Look over your own shoulder and keep asking, why the hell are you doing that. If you can't explain why then you should probably be fired. (some people are not cut out to be day traders)
So you live off a pension or you received a huge settlement when your foot got stuck in an escalator?
I apologize in advance if this comes across as a little crass, but your question is simply meaningless. If your friend is profitable with ONLY ONE TRADE PER DAY, then by all means stick to that strategy!!! Who sez you MUST make more than 1 trade a day? If you were my friend and you tried (deceptively or otherwise) to steer me away from my already successful setups, I would smack your face without any hesitation. Because that ain't no friend of mine. I know, truth hurts.