The tenant just needs to show that the drive is not fit for purpose, http://www.pavingexpert.com/subbase.htm for example
even though it had a small car using it I bet it would it have sunk with a bigger car used by a fat family

Range Rovers weigh in at about 3.5 tonnes and are classed as a PLG or private light goods vehicle. Vans up to 3.5 tonnes are also generally classed as PLGs

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"The person who never made a mistake, never made anything" - Albert Einstein

OK, I'm an "old school" chippie, so please don't ask me to do a bodge job - I didn't bring my horse today and in any case you don't seem to have a hitching rail!

No argument about the weight as such. Plenty of heavy cars and PLVs. Motor homes are another example.
As I said my argument would be that the van might well be the guy's self employed business van, and hence parking it there could be seen as breaking the "no business activity" clause on the tenancy agreement. If there is one of course.
If it was my house I was letting out, I'd be well brassed off. The fact that the drive wouldn't take that vehicle must have been obvious for some time before it was torn up as badly as it was in the end. So why didn't he stop parking on there?
I reckon he could at least offer to pay part of the cost of the repair whatever the legal case may or may not be.