Open up engine because rpms are not stable and he doesnt know? Thats not a mechanic atleast. Mention your location so u may be get directed to a better one or take it to Honda.
Issues with RPM etc are usually due to throttle body, which has been through ustaad ki safai multiple times, draining its bushing lube, jamming it up. In your case, it seems iacv is either stuck shut or the butterfly itself isnt moving. Nonetheless, get it properly diagnosed, and do not let that mechanic touch it again (let alone disassemble the engine).
