the way i read it the source doesnt apply to your nephew on the following chuck:

battery terminals: (nothing in the regs about covered terminals, although it makes sense, but on a portable battery operated boat, its almost pointless.

secured battery: again no reg requiring this, especially on a car top boat.

Flares, horn: sound yes, flares or visual signal no. he needs running lights is he is out there at night, but flares on a 12 foot boat are not required inland. he also doesnt need a fire extinguisher. get him a whistle, attached to a laynard on his lifevest. problem solved.

most of it is suggested, i would suppose. none of it is a bad idea, though.

ive been in my 8 and 10 foot jonboats more than ever this year. light, registration, float plan, whistle, lifevest on at all times, and im good to go and legal.