Thats a big dude but its not impossible. He would just have to be very dedicated to lose all that fat. I had a buddy who was around 380 and now is 190. Took him about three years to do it but he did. Eats one big meal a day and walks 8 miles every single day. So yes its possible but all up to...
Im not from New York but i know Renzo Gracie has a school near you. Also i would take some kick boxing the combo of jiu jitsu and kick boxing is tough. Since you wanna kick peoples ass it would work out great.