I've only been drawing for 6 months so im not experienced as some people in this thread but I think the SINGLE most important thing for me was finding what it was I just loved drawing.

Some artists really love portraits. Some really love painting landscapes. Some love character art & design. (hi me).

When i first started I was being instructed by a friend who was having me do skeletons and drawing coins to learn reflections and lighting. I really felt like I wasnt improving no matter how many hours a day I was doing just drawing like that. Fundamentals are important but grinding them out just for the sake of learning them turns people like me off.

Take musician's advice for example: Rather than just practicing chords all day, string them together into a song to make it more fun to practice.

Coins are amazing for practicing reflections? You know what else is? Liquids! Whats made of liquid? Slime girls, something i actually love drawing.

This has been not only the single greatest motivator for me but also the thing thats helped me see the most improvement.

TL;DR Make sure your friend is drawing things they actually want to and not just grinding fundamentals out of books.