Yes, Manny can still fight professionally if he chose to do so but he knows well that he ain't the same Manny anymore that the people knew and his skills are not the same when he was still in his prime. It's still a good idea to do some fights in the form of exhibition fight and that way he can still do his passions in boxing.
Maybe soon, we can see him running for a senatorial seat or maybe he will go back and run as a congressman.
yes, he can still fight but I don't think he would risk to tainted his record with losses upon his retirement, I think he had already felt it in him that he can not last anymore it is good for him to just focus on exhibition matches that are not that risky even an amateur can surely go and fight with a well known retired boxer, for me DK Yoo is an amateur boxer and he will likely be pursuing his death wish fighting Manny Pacquiao,
And speaking of exhibition matches Jake Paul is challenging Anderson Silva, I think Jake Paul has a death wish aswell,
Do you seriously think Manny cared much about his record like Mayweather? Manny did not duck a single fight, who ever comes up to the table he'd always gladly accept every challenge that comes along his way all throughout the 8 divisions.
He decided to resign because he has done more than enough and father time is already calling.
Also, nobody is having a death wish in an exhibition matches. DK Yoo or even Jake Paul is also trained to be a fighter. While Manny and Anderson are all past their prime. This isn't a serious match anyway.