Your brother's problem doesn't arise from a backward step. It's due to the lack of a forward one by him.
In the 'old days', with analogue TVs and VCRs, both devices had their own (analogue) tuner built-in. It was therefore possible to record one programme, while viewing another, because the tuner in the TV fed a signal to the screen while the tuner in the VCR fed a different signal to the tape. Similarly, it was possible to record a programme with the TV switched off, because the tuner in the VCR was still switched on.
He's now got a TV with a digital tuner built-in but, presumably, his recording device (VCR? DVDR?) hasn't got its own tuner. Therefore he can't watch one channel while viewing another and he can't record with the TV turned off. To get back to the situation where he can do these things, he needs to upgrade the recording device by either buying a new one which has a built-in digital tuner or (cheaper) by buying a Freeview box as a tuner to be used with the existing recorder.
Chris