Hopefully some will respond that has that specific plane figured out. But, ...

How heavy is the nose wheel? All my tricycle geared planes are not very heavy on the nose wheel. ( Just kind of a gross indicator of a CG problem.)

Also, is the length of the nose strut correct? It could be too short thus raking the plane with the nose down.

Did he have the right battery in it? (e.g. 5S vs. 6S?)

The reason I even responded is; We had a pilot with a similar situation. He ended up with a crashed plane. His plane was simply underpowered. They frogged around with moving the CG back to get it to rotate. Then the plane rotated. But then, ... it almost immediately stalled and crashed. His plane simply did not have the power to climb at a reasonable rate given the configuration of the wing. It was an F-105. The Interceptor kind of appears to have a relatively similar sized and shaped wing.

We also had an F-14 that was underpowered and it took a very long run to get it off the ground. It eventually flew. But it too stalled and crashed. And we know that its GC was spot on. We figure it to was just under-powered.

A couple of instruction manuals I have read specifically address the nose strut length having to be correct to allow easier rotation. Think the Sprint may even be one of them. ( I read a lot of Manuals.)

Good luck. Be careful if you are flying your bud's plane.