That's because when your car was struck while parked, it didn't involve a moving violation on your part. (Unless you left it parked in the middle of a freeway).
Depending on the circumstances which, again, you didn't bother to describe, your vehicle might have been covered under Section 6, Direct Compensation - Property Damage [DCPD], with you 0% at fault; or under Section 5, Uninsured Automobile, if the the other driver was uninsured BUT identified; or under Section 7, Own Damage [collision or all perils coverage], if the the driver who hit you was not found. There would be no deductible applied under Section 7 either because you were 0% at fault.
(Even though the accident was caused by another motorist, under the no fault provisions of the Ontario Insurance Act, your own insurer would have paid.)
Conversely, when your husband lost control of his van there was only one person who could have caused the accident (unless he was forced to swerve to avoid another errant driver) and therefore he was 100% responsible - or "at fault" as they say in the industry. The only possible section of an Ontario auto policy that could apply to this case would be Section 7, Own Damage. 100% of the deductible would be applicable since your husband was 100% at fault. (If he were 50% at fault in collision, only 50% of the deductible would apply).
Of course, if he damaged other people's property when he collided, he would be on the hook for that damage under Section 3 [Liability] to the percentage extent he was found at fault by the claims adjuster. In this case, that didn't occur.
Ray