It's always the company's fault: either they didn't vet the candidate for good culture match, or they didn't provide a good Jr. Ramp up plan (being a jr dev remotely is extremely though), they didn't provide clear/firm enough ongoing feedback and as you said, they didn't provide the right expectations.
For a Jr remote SWE position, I would expect heavy pair programming the 3 first months.
There's a basic expectation that people should be actually showing up to work. How can you possibly vet during an interview that someone will be flaky like this? Sometimes people just don't have a good enough work ethic that meets the basic expectations and no amount of ramp up plan or initial feedback is going to produce changes quickly enough to make continuing the relationship worthwhile. People like this are just constant ongoing headaches. Thankfully, they're in the extreme minority in my experience.
Although I would cut some more slack for the background noise during calls. Not everyone has separate rooms they can work from. Instead, the company should have sent him a good headset to use which would mute background noise. Sometimes my coworkers will apologize for their dogs barking and I'll say I can't hear anything when they are using a good headset.
For a Jr remote SWE position, I would expect heavy pair programming the 3 first months.