If he had no taxable income during his time in Colorado, then he would not need to file a return. If he received taxable income while a resident of Colorado, then he will need to file a return for both Kansas and Colorado.  

"WHO IS A COLORADO PART-YEAR RESIDENT? A part-year resident is an individual who was a Colorado resident for only part of the tax year. This includes a person who moved into Colorado during the tax year with the intention of making it their home and a Colorado resident who moved out of Colorado during the tax year with the intention of making their home elsewhere. A part-year Colorado resident is required to file a Colorado income tax return if they: 

• ? are required to file a federal income tax return, and 
• ? had taxable income during that part of the year they were a Colorado resident, or had taxable Colorado source income when they were not a Colorado resident." https://www.colorado.gov/pacific/sites/default/files/Income6.pdf