As Eddie says, common assault is for the magistrates. Section 38 is assault with intent to resist arrest, not threatening to kill, if that is what you mean by 'alleging' (threatening to kill is section 16). Perhaps your friend said something as an idle threat when being arrested; people often say "I'll kill you" without actually meaning the other person to believe a word of it. For section 16 to be charged they have to intend that the other person will believe that the threat to kill will be carried out.
If it is just s38 and common assault it sounds as if, like Eddie says, it will be dealt with by community service, or a fine