My son was in the Army, has been diabled by the military and has lived in my home for the more than past year. Can I claim him as a dependant?

If you are paying for more than half of your son's support, he lived with you all year and his taxable income is less than $4050, then he is your qualifying relative and you can claim him on your tax return. For more information, see below.

https://ttlc.intuit.com/replies/5659686

Does your son count as disabled under the IRS tax rules? 

A person is permanently and totally  disabled  if both of the following apply. 

1. He or she can't engage in any substantial gainful activity because of a physical or mental condition. 

2. A physician determines that the  disability  has lasted or can be expected to last continuously for at least a year or can lead to death.

If your son qualifies under those rules and If you are paying for more than half of your son's support, then he would be your qualifying child. You would be eligible for the Earned Income Tax Credit, but not for the Child Tax Credit.