A will made after a marriage can a spouse still disputed it?

The wife would have the legal ability to challenge thw Will in probate court once it is filed there after your father-in-law's death, not before.  Will contests are very difficult to win, however.  As long as your father-in-law understood the Will and signed it voluntarily with two witnesses, it probably would be found valid despite the challenge. Please note that most states, and Wisconsin is included, have laws that allow a surviving spouse to receive part of their deceased spouse's assets even if the spouse is not included in the Will.  Such laws are to provide for a surviving spouse, and do not take effect if the surviving spouse receives adequate assets from property owned jointly with the deceased spouse or for which she was named a beneficiary, such as retirement funds or life insurance.  The surviving spouse has to file with the probate court after their spouse's death in order to receive this share.  The rights of a surviving spouse are not dependent on the length of the marriage.