Hello Sir/Mam,

If your son lies under SC reservation category in central reservation list available on the official website of NCBC then definitely he would be eligible for SC quota in Rajasthan and as he already has domicile of Rajasthan so he can appear for NEET UG counselling for state quota seats of Rajasthan but note that SC certificate of Karnataka would not be considered for counselling of Rajasthan's medical colleges so make sure to apply for the SC certificate of Rajasthan or apply for central SC reservation certificate for your son. Only after having the SC certificate of either Rajasthan or of central authority, your son will be come eligible for SC quota in state quota seats of Rajasthan.

For complete details about NEET UG Rajasthan counselling kindly check out the link given below :-

Rajasthan NEET Counselling 2021 - Round 2 Dates (Out), Registration (Started), MBBS/BDS Seats (careers360.com)

I hope this information helps you.

Good Luck!!