Liszt's Hungarian Rhapsody No. 11 (very beautiful, short, and not too difficult--although since he just completed No. 2, it might be a little too soon)
Transcription of Verdi's Rigoletto (fast scales and arpeggios but also not too difficult)
Gnomenreigen S. 145 (very fun)
Liszt-Paganini Etude No. 2 (La Campanella is also an option but I don't know if he would manage)
Transcendental Etude No. 1, 6, 9, 10 (6, 9, 10 may be a little too difficult... 1 might be too easy considering his completion of Chopin's Scherzo #2)
I personally think Valsee Oubliée is a great option.