If his mother was listed as the nearest relative that would indicate his father had passed away. Having left after WW I perhaps his father was killed in that war. It is not difficult to know whether they were using their mother or fathers name! Of the hundreds of manifests I have found I can only recall one case where the mother's maiden name was used. In most cases the father's name was used.
Did you notice that on the second page he listed his destination to a brother in law Josef SOHONHERR?
Do you mean Trieste, rather than Teresta?
I am puzzled as to why I can not find Leopold PENDL in any us census or social security records nor do I find a Marie (which is more likely Maria) PUTRE in immigration records. Can you tell us what you have found thus far in US records and under what name?