In the absence of further information, a decent start might be to give each student with special needs (be they due to giftedness or disability) the same amount of effort or funding. At least in terms of federal funding (because it's easier to aggregate across the U.S.), one Google result[1] says: "The federal government does provide GT funding to school districts through the Jacob K. Javits Gifted and Talented Education program. The funding for the Javits program is $12 million annually, which equates to $2.50 to $4 per GT student in this country." I think I saw an article saying the current administration proposed canceling it, but it seems that hasn't happened.
Meanwhile, in terms of special education: "Ever since its initial enactment, the federal law has included a commitment to pay 40 percent of the average per student cost for every special education student. The current average per student cost is $7,552 and the average cost per special education student is an additional $9,369 per student, or $16,921. Yet, in 2004, the federal government is providing local school districts with just under 20 percent of its commitment rather than the 40 percent specified by the law, creating a $10.6 billion shortfall for states and local school districts."[2] Well, if they currently pay about 20% of $7500 per student, that comes out to $1500-ish.
So that's a difference of ~400x. Not that I think the federal government should be funding such things, but given that it is...
[1] https://ednote.ecs.org/do-we-really-need-to-fund-gifted-prog...
[2] http://www.nea.org/home/19029.htm