To me, infantile convulsions would sound like febrile seizures (from a fever), except that you mention quite a few of your relatives died of this.  Febrile seizures in infants are not so uncommon and not  usually fatal, even without some Tylenol or aspirin.    Even without some drugs, parents of those times would usually be able to cool a baby down, too, to reduce fever.  Those cold compresses really do help! So I wondering if it is not some seizure disorder that's genetic. Linda   Pediatric RN