Probably lost the COM aerials in the crash, and maybe was a bit leery of switching the master back on. A hand-held VHF COM unit is something I always carry. Plenty of high altitude traffic on centre frequencies or 121.5 if you like.
My guess is that his external ELB aerial was also torn off by the bush as he scraped through it - and he didn't have a portable one carried inside the cabin.
The outcome was good, but leaving the wreckage and walking off that distance goes against all the advice on survival.
happy days,