People laughed at John when they saw him

[Bassim]

I am wondering if my sentences are grammatically correct.

People laughed at John when they saw him at all times of the day picking up discarded cans and plastic bottles from litter bins. About ten years later, when he bought himself a flat, nobody laughed at him anymore.

 

[emsr2d2]

They're grammatically correct though they rely on the reader knowing that he can get some money for those cans and bottles. If the reader isn't aware of that, the two sentences would appear to have no connection.