Smoking could be contributing to the wheeze of your grandchild, especially if mum smokes inside the house, in the car or around the baby even if outside.
I myself am a smoker, but do not smoke around my son, and regretfully took it back up again after I had him.
If the wheezing is chronic like suggested, I do question the fact there is no mention of the baby not having been to a doctor.
My son developed a wheeze overnight and the very next day I had him at the doctor. It turned out he had bronchialitis, which can be a pre-cursor to asthma, something they are loathe to diagnose while baby's airways are small. But to get it diagnosed as each bout occurs builds up a history so that when the time comes they know that it isn't an isolated incident.
Possibly Asthma by: Anonymous
Have you considered that what you're seeing is possibly asthma? I know that they say 2nd hand-smoke is a whole lot worse than 1st hand. I would possibly look into asthma and try to avoid the potential causes. But regardless, inhaling any kind of smoke cannot be good for any baby.
Try to eliminate the potential causes of asthma, see what happens and then let us know. It would be interesting to know.