Now it kind of looks like the messenger cable is also the neutral conductor.
And look at the differences in cable ODs between what goes into the house and what comes from the utility pole. The pole wires must be 1/3rd the diameter of the larger cables on the left. I'd guess the nominal 240 volts must drop quite a bit when all the 240v house appliances are on.
Here's pics of bolt to bolt fasteners.
Use a threaded rod going into the house because the length required is probably unknown. The rod should go through roof structural members, not like how they appear to have done it in your photo.