sounds like he got caught by a gust of throttle stick, wind my ass.
this repair is gonna very expensive, he better get a lone.
get a new prop, spinner, then simply cut back the damaged wood until you get to undamaged. scaft joints ( at an angle ) will give more strenght than one that is straight, in this case parlell to the firewall. the part hes damages sounds like the cowl, which has no load on it at all and will either be 1/8th ply or 1/4 balsa. then get a roll of covering to match that part of the plane. it'll take an afternoon and cost less than the prop

have a look at my rebuild page to see the basics

www.philsrcworld.fsnet.co.uk