I agree with Leadfoot. Since you have multiple gear pieces, just pack a set for your dad and surprise/impress him. To minimize any reservations on his part, pick a nearby hike and make it short (e.g. an overnighter or something). Hopefully, once he hikes with his 'new' gear, he will be hooked.

Some people learn quicker by actually seeing/touching a ready-made alternative rather than analyzing and coming up with it on their own from scratch...