H1B transfer company payroll mistake

Hi Anil,

My brother is on H1 and had got H1 approved for other company offer but didn’t joined. Don’t know for sure but may be by mistake other company couriered pay cheque to him showing as he joined company. Payslip indicate all taxes paid, employee id generated etc.
Now he has not deposited those cheques also but what are the consequences of this ? In future stamping or taxation, and do he need to have that H1B original copy for all future immigration matters.
Taking a letter from other company will it solve any of these possible issues ?
Please advice.