changing meaning with 'have'

[Tekoyla]

Yesterday I was behind a hobo in line at the supermarket. Only now I've realised that he couldn't have afforded the things he bought. - This sentence is questioning the fact that the hobo had money for the things he bought but in the end he bought them. , ?

Yesterday I was behind a hobo in line at the supermarket. Only now I've realised that he couldn't afforded the things he bought. And this means that he wasn't able to afford those things so in the end he didn't bought them. , ?

so my question is that 'have' can change the meaning of a sentence ?

[Mister Micawber]

Both sentences suggest that he bought the items. Please compose simpler sentences for comparison if you wish to pursue your question.
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Native English teacher at Mister Micawber's

[Tekoyla]

First of all, what's the difference between the two sentences ? btw, MR Micawber I sent you a personal message - please read it :)