<Snipped quote by Lmpkio>
How would he know how to? Making a Friend Heart requires a specific action, and to do that accidentally would be one heck of a coincidence.
That's the thing, he wouldn't recognize or know what he did was that specifically. And being a character of Star Road, maybe it's a bit more feasible with the magic in some way?
Of course, I can always just have Geno "kill" him, have him hold on to his spirit core, eventually find his way to the Master of Masters and be told how to revive his friend from him. If you prefer the latter over the former, that's also completely fine.