Just came back from an inspection that had a 60 amp 120v service.
So you're saying this mess was protected by a 60-amp 120-volt service disconnect breaker/fuse elsewhere? Because the way it is hooked up is actually a 120-volt
200-amp main (albeit only feeding a total of 175-amps worth of breakers) and that feeder would be woefully undersized if not protected by something else "upstream". If it is, the 100-amp double-pole is really just a convenient set of lugs and acting like a main shut-off.
I've never seen a 120-volt service or a jumper like that and have no idea if that would be the "correct" way to do it, although I'm not sure I can think of anything actually wrong with the method (assuming correct wire sizes, etc). However, there's too much else wrong to worry much about this and...it's "Sparky Time".
Added after seeing the second photo...
Ummmm, there's no other protection? Well....then it's
very scary wrong!