For new traders, they recommend 1% of capital which is $4,500 per trade. Place a hard stop loss after entry too. Most times, you do not lose 2% (total loss), maybe, 0.5% or 1% tops. So, even after several losses, you are still A-Okay with most of your capital intact.
18months, seen people lose 100K in weeks, bright future, just got to build his margin only money via Mini's back to the 550K won't take long. $200 losses, scare the crap out of me and get me all emotional, so not surprises if trading with that kinda $$$'s. Operation funded and it's not my money or real money just numbers on the screen I think, to take the pressure off, he should try LeeLoo much less rules than TopStep.
It doesn't mean swing traders have a higher chance of success. The success rate for swing traders could be around 10%.
It is easy if automated. Just code your Algo to bet small initially and then ramp up quickly as profits are made. Tell it to cut back when losing, especially when near the initial account starting value.
OP, I would discourage your friend from practicing dentistry as well even though you've taught him to brush for an entire two minutes.