If you are in a US school district, the chances are extremely high that a written request will not result in testing during this school year. Even given differences in how states have operationalized the federally-mandated due process timelines, at this point in the year, most districts will not have to complete the process before the end of June/beginning of September. And yes, if they can push it off, they probably will, with the floods of end-of-year critical items. It's just triage. I would second asking about summer testing. Some of the big districts in my area do retain staff to do summer testing.
But given that the formal GATE program doesn't begin for a few years, do you really need the official GATE test to access alternative services? He already has (if I recall correctly) a perfectly usable SBV ABIQ. Maybe what you need is a meeting with GATE decision-makers, rather than actual testing. That might be something that could be set up for this summer. Are you in a state that mandates addressing gifted needs in a special ed IEP?
