What happens to endowment if there's a crash?

I've been asking a few questions about investment on here (in the Investments section) of late and been very grateful for the knowledge I've gained from people who have answered and just by reading the answers to other people's questions.

I'm now wondering about my friend who has an endowment policy with Royal London.

As I'm invested in shares/bonds etc via Vanguard LifeStrategy I'm fully aware that if there is another crash or "rebalancing" of the economy my investments could suddenly drop in value by a massive amount, but if this did happen I'd just need to hold on and hope that over the next few years they recover their value - I'm in it for the long term.

My friend's endowment is with Royal London, it's been going about 23 years and has another couple of years to run. It's aiming to produce about £26,000. She is still paying into it regularly and intends to continue.

So my question is, what would be the implications for her endowment policy if there were a crash? Would the current value of the policy be preserved but there'd be no further growth or would it go down in value? Currently, she seems to think it's doing quite well.

She no longer needs the policy to cover a mortgage so it'll all be cash for her use. I suspect a lot of endowments never make it to the end but she's determined to see it through.