I actually just held it overnight the second time. I had sold all my ETHE shares on the 3rd because I didn't want to hold it going into the holiday weekend. My account was just sitting in cash for the next 10 days, and then yesterday when everything tanked, I noticed the afternoon price for Greyscale ETHE shares was hit harder from the volatility than the actual exchange price of ETH, creating a pretty large relative gap between the prices of ETH and ETHE, and assumed that the price of ETH would rise overnight and the market open price for ETHE would rise even faster to catch up as both prices regressed towards the mean after a bad day. It paid off.She held it for like a week. It will be taxed at her personal income tax rate.
You've given zero indication you even know how taxes work.
Spoiler: You only pay taxes on your profits. If you take losses, you can use those to offset other income.