If your son's W-2 only has an amount in Box 1 and the rest of the boxes are blank, it generally means that the income reported in Box 1 is taxable. Box 1 on the W-2 form represents taxable wages, tips, and other compensation
This amount is subject to federal income tax. - if the grant required your son to perform services (like working as a lab assistant), the income is taxable.
To enter your W2 as noted by @Bsch4477 follow instructions at this link.