What would be your advice: Persevere or cut your losses and move on?

@mom2and & @Hunt: Right, you have to be superelite in the field to make the NBA and (usually) to be paid to sing.
Typically not to get a job as an engineer.

But if someone is years behind in math (has a shaky foundation that would take years of practice to fix), majoring in engineering just isn’t going to work out at this point in time.