Relative to $20k it might! But if it doesn't make much of a difference to you, feel free to send 5% of $20k to my Stars account...
$20k into £ at 1.99 (todays rate) = £10,050
$20k into £ at 1.94 (lowest this year) = £10,309
$20k into £ at 2.03 (highest this year) = £9,852
So the dollar has fluctuated by a max of $0.09 to the £ which only gives a difference of £457
In reality, the $ has only fluctuated by $0.04 in the last 4 months ($1.94 to $1.98) which is a difference of £208.
This assumes he wishes to cash out all $20k (which I doubt) . So if he only wishes to cash out half, then the max swing on $10k this year has been £229 and in the last 4 months only £104.
Not exactly relative imo.
It could even be counter weighed by any interest gained once in the bank