Dieing / burnt leaves towards the end of flowering

My friends plant is in the last month or so of flower and he's getting dead leaves. My old plant did this towards the end too. Wondering if we should flush her or if this always happens or what's going on.

Thanks

Is this soil? Looks like that plant had been receiving plenty of nutes. Possible lockout?

Yea its soil. Ok, we'll flush it.

In the end the plant will be using it's stored energy to develop bud growth. When doing this it's natural for some of the larger foliage to begin to slowly deplete.

As far as flushing goes you should always do that several times throughout the last several weeks of flower