Actually, OFP can do most of the work for you. You may or may not know that the text you type in the "text" field of a radio trigger will be the text shown in the radio menu (I didn't know that for a while). Well, it gets even better than that, because OFP won't display that radio command until that trigger can be activated.
Normally, a radio trigger only has "this" in its condition field, which means "activate when I use the radio". But you can add other commands in there, like "this && alive bob", which would mean "activate when bob is alive and I use the radio". If bob were to die, there would be no way to activate the trigger, so OFP would just hide the radio command from you.