There are a couple of things we can do and I am guessing this attack might be informed as in, someone knows the victims had Bitcoin that is worth something because I don't think it was random hence the need to keep quiet about your cryptocurrency HODLing in the first place.
Another thing is that you can have a separate smartphone you don't take around for your crypto transactions if you are going to install all the wallets and apps in there and most especially if you have such amount of Bitcoin is to store on a Hardware wallet. Though it is almost impossible if such attacks happen for you not to give out the info cos of the safety of your loved ones.
There are cases like that before where the suspects are related to the victim because they know when to attack or lets assume that is not the case but there are also robbers that are highly intelligent and they have been using bitcoin before. They have done online crimes apart from face to face crimes.
At the end of the day, bitcoins are only a kind of money that we can still be earned but not our life once it is lost. If we are on that dangerous situation, we are also going to do the same which is to surrender our bitcoins into the criminals hands and let us not worry because bad karma will still follow those people .