Family member has about $150k basis between ARKK, ARKG, TAN and PBW.

I looked into a family members account and see that they invested during covid, made a bunch, but then didn't sell before the fad ended. They are now looking at about -80% (if I recall correctly).

What is the general consensus when massive losses are taken in funds like these. Ride them back up? Or cut losses and invest in something less volatile? $ARK Innovation ETF (ARKK.US)$ $ARK Genomic Revolution ETF (ARKG.US)$ $Invesco Solar ETF (TAN.US)$