Seems pretty clear-cut to me.
The customer should have been way better prepared - I'm a wheelchair user, I never expect people to help me with things into the house unless I have specially arranged for it. If he is in this situation regularly, he'd probably be aware that lots of companies can be funny about drivers going into people's houses without pre-agreement because of health and safety. Most drivers will be fine with helping you get something in the door, but it's hit-and-miss whether they'll do more than that. Living with this kind of condition is a massive, draining pain in the arse where you have to plan every single little bit of your life with military precision. It's genuinely exhausting.
All that said - the driver is a **** - it doesn't fall on delivery drivers to pass judgments on people based on who they think has a real disability, like many in this thread are doing. You are not doctors and haven't got a fucking clue what this bloke's life is like, he could be suffering the kind of fate and pain you wouldn't wish on your worst enemy, yet many are still happy to call him fat and lazy. In the years before my disability became plainly visible, I got shit fairly regularly in a similar way to this, but it was mostly never worse than people staring at me or making a vapid comment for using accessible toilets. This country's ability to make the most downtrodden folks in our society who are suffering feel like a burden is genuinely something to behold. We have turned into a country that's completely devoid of compassion, and this bloke is a prime example of the type of comment which you will face daily if (heaven forbid) you have the gall to suffer from a disability.
It shows that people genuinely don't know what it feels like to be in constant pain, exhaustion, anguish, and then have some jumped up little snivelling weasel who knows fuck all come along and tell you that you're faking it. If you think that kind of thing can't drive people to suicidal ideation, then you frankly don't have a fucking clue. Am I saying it's like that for everybody? Of course not. But even if it's like that for 10% of the people suffering, or even 1%, why take the risk and open your stupid fucking mouth?