If you are up for a 17-19 hour drive it is possible. I personally would never recommend such a long drive with a family specially if there is only one driver. Usually travelers break journey at Naran. Expect the below timelines as of 2 days ago:
Isb - Naran 7-9 hours depending on time of day
Naran - Babusar 2.5 hours
Babusar - Chilas 1 hour
Chilas - Gilgit 1.5 hour
Gilgit - Hunza 2.5 hours
Hunza - Khunjerab 3 hours ideally (it snowed yesterday so could take 4 - 4.5 hours)
To summarize:
Isb - Naran 7-9 hours (10 am traffic starts to build up in the haripur - abbotabad section with wagons, trucks and buses ruining the drive for you and it stays busy till around 2 pm.) I always leave isb at 5 am and drive to abbotabad in 3 hours to have breakfast in abbotabad at a very reasonable 8 am. From there, you are ahead of the traffic. open roads, beautiful early morning scenery and a comfortable 4 hours to Naran)
Naran - Hunza 7.5 hours. Road is perfect in this stretch.
Naturally you would want to stop for lunch and tea along the way so add 2 hours for that in each leg. Also, fuel up, pack vehicle with luggage and verify tire pressure the night before to avoid delays the next morning.