Cuilfaen
I wouldn´t recommend buying 5 decks at once as well. Not only because it might be confusing for someone just starting out, but also because then there´s not only the pressure to find "the one" Tarot (which honestly you usually don´t find right away anyway) but the five "right ones" (a money issue as well: I mean your friend is investing some money purchasing five decks at once).
I started out with a deck I liked visually (but couldn´t connect with properly as I found out on my way working with it). But because I had this deck, I came clear about what I was looking for in a tarot deck. So the next deck I bought (years later) I loved dearly. And the one after that was a "love at first sight" purchase and so on. So even though nowadays I´m very rarely using my first deck, it´s definitely been a great steppingstone for me.
I think your friend should just start out with one deck, he or she finds appealing, no matter what tradition (RWS, Thoth,...), and work his or her way from there.
I started out with a deck I liked visually (but couldn´t connect with properly as I found out on my way working with it). But because I had this deck, I came clear about what I was looking for in a tarot deck. So the next deck I bought (years later) I loved dearly. And the one after that was a "love at first sight" purchase and so on. So even though nowadays I´m very rarely using my first deck, it´s definitely been a great steppingstone for me.
I think your friend should just start out with one deck, he or she finds appealing, no matter what tradition (RWS, Thoth,...), and work his or her way from there.