He should use the bike then. Who is asking him to drive the car by sitting alone in it? I know many people who use bike while going alone, though they have car as well, which is used when people more than 2 needs to go out.
So the bottom line is, we are supposed to use the things which we can afford, we should avoid those which we cant afford.
CNG was introduced and promoted with an objective of using green fuel. But as soon as the diesel vehicles started using it, it is becoming scarce. A bus is equipped with six big size cylinders, which can fuel at least 6 cars.
I personally know few transporters, who never bring their buses out when there is strike of cng. They are part of mafia who are charging fares as if they are using diesel, but they have never used diesel since they got their buses converted to cngs. So the ultimate poor, who cannot even afford bikes are simply helpless and main affectees of this CNG and transport mafia.
I am of strong opinion that there should be blanket ban on CNG, even if they intend to allow, then it should be available for cars below 1000cc.