Ethereum to $100 is not possible, for Ethereum to reach $100 again that means that the market is so bearish to an extent of the fact that bitcoin crashed so much, so don't expect $100 for Ethereum price again
If think that then now ETH is falling and BTC price is increasing, so it is clear that their is no relation between ETH and BTC. Even if ETH price goes to $100 or more low BTC price can increase or decrease but both coin relation is different. Right now everyone is sell altcoin and buying BTC as they expect the bitcoin price to move up in coming days.
If BTC will fall to 3000 ETH will see new bottom 100%, and if BTC will grow again all will grow with it. BTC don't depends on any other coin, but eth depends on 100% imho.
IMHO ETh could reach 100$ but this will be for a very short period of time. I would advise to put some buckets on low volume exchanges to catch some big panic sellers.
In some cases ETH will follow the price movement of Bitcoin, but not always. Can you explain the recent Bitcoin pump a few hours ago it went $6.7k while ETH remains at $290 and didnt even moved. I though ETH depends on Bitcoin 100%? Why did it fail?
I guess people are dumping most of the alts including ETH, that is why we didnt see ETH recover even a little.
And lastly, the OP shouldve said "ETH to $100, buy more"