You did not mention if your uninsured motorist was for bodily injury or property damage so we will assume it is bodily injury since that is the most common type of uninsured motorist coverage that is available. Also, we will assume the UM is coverage on the van.
Uninsured motorist bodily injury normally covers you (the policyholder), the insured members of your household and your passengers for bodily/personal injuries, damages or death caused by an at-fault uninsured driver. If you are involved in an accident where the other driver is at fault but has no insurance, your policy will cover your medical expenses, up to the limit on your policy.
If the limit of your UMBI policy is $25,000 then your wife's medical bills should be taken care of up to this limit. If her medical expenses are less than this amount than the payout or settlement will be for the medical bills and if your policy terms allow for it pain and suffering as well as loss of wages.
I believe you are writing from Louisiana, if that is the case you may choose to purchase uninsured motorist economic-only (EOUM) coverage. If this is the type of coverage that you have, it is the same as uninsured motorist coverage listed above except that it covers only the actual costs of injuries to you and the occupants of your vehicle. Pain and suffering are not included under this coverage.
Uninsured Motorist Damages (UMPD) pays for damages you sustain to your covered vehicle, which does not carry collision coverage, and is caused by an uninsured vehicle. If you do have UMPD, then your totaled van should be covered. Your policy would pay out what the actual cash value (ACV) is of the van or if the ACV is more than your policy limits, only to the limits of your UMPD policy.