Kot, SV cooking was developed by restaurant chefs as a technique to safely separate cooking from reheating for service over lengthy periods of time. Steaks, tenderloin roasts, and chicken breasts are among the most frequent menu items used. Thousands here have also done it.
To be safe just cook at the appropriate combination of time and temperature to ensure complete Pasteurization. That means past Rare doneness by cooking at 131F or higher over enough time to achieve temperature equilibrium throughout the roast. Be sure to thoroughly chill the roast in an ice bath for several hours before refrigerating it.
Inform your lucky friend on how to bring the meat up to its cooking temperature and then brown it just before enjoying.