Silver has nothing to do with making an all-white chicken. You cannot make a solid white chicken with just silver. You need either Dominant White on Black or Recessive White in anything. They may or may not have silver.
For an all-white chicken with dominant white neither the dominant white nor the black needs to be pure, the chicken can be split for either or both of those genes. If they are split and not pure there is a much greater chance of leakage, though leakage is not guaranteed. If silver is present it will lessen the chance of you seeing red leakage though it can still happen. I’ve seen red leakage on Meyers red sex link males based on their Rhode Island Whites. Those birds did not have barring. A hatchery bird is not likely to be split for either gene, but a bird from someone’s flock might. If the genes are split, you can have a lot of other stuff under there.
Since Ideal uses them for their red sex links, it’s pretty sure they are recessive white and that they have silver. Recessive white is really powerful when it pairs up, it can hide practically anything. But if it is split, it’s as if it is not there.
My guess is that the mother is pure for recessive white, has silver, and has barring hiding under the recessive white. That’s not unusual, breeders often add barring to white birds to make them look even whiter. The solid white mother is going to be based on one of the red genes, could be anything other than Birchen or Extended Black. That pattern is classic Columbia. That cockerel does have the color and pattern of a Delaware, the barring does that.
If you crossed that hen with a black rooster, I’d expect you to get black sex links because of the barring.