Medicaid waiver payments received for a qualified family member living in your home are considered "difficulty of care payments" and are excluded from federal gross income. This means that box 1 should be blank or show 40.
However, you cannot e-file the return with a W-2 with a blank box 1. You should leave this W-2 off for your federal return.
Note that while this income is tax exempt for federal, some states may still tax these payments - so check your state's specific rules on whether you have to add this income back to the state return.