Isn't the 3 part flora a complete MAIN NUTE? I understand it is not a complete line. They have all kinda of additives you can put in which I also own. Like calimagic, florablend, diamond nectar, rapid start, floralicious, liquid koolbloom. But he said first time grower and telling him all that stuff is needed for a first time grower is a bit over bored especially for soil. If it is in soil I'm sure the 3 part alone will give you some results may not be the best but i am sure he will be excited to see he magically grew smokable bud from a mere seed.
OH sorry I kinda said you told him it was needed. Just noticed that. oh and I didn't know he was growing in soil when I posted that. GH makes a 2 part nute perfect for soil called floranova. Comes in grow and comes in bloom and you only have to use one at a time.
I would think that would be super simple for a beginner. Mind you it is on the strong side but just remember, less is more.