Or best still, you could split your wallet phrase into two half, since it’s usually 12 wallet phrases, you could give a member of your family the first six phrases and then the other six to your lawyer, and you could tell them the importance of those phrases, so they’ll know well enough to guard it well, and this way, the only way to access this funds would be when they both provide their own halves of the phrase. I believe this is a more preferable option because they may not even know how much is in there and they may never get to find out until after you’ve passed and it’s time to open the safe.
And this is actually a good idea because from the beginning it should be both sides you can not trust anyone one this is enough reasons why people need to be creative because there family member that are ready to loot you but at least if it shared then if there is something your family can request for any day any time.
I don't think the law firm will put there reputation at risk just to steal your funds so of you are not fully comfortable with that of your family you can just fully put everything in the hands of the lawyer and make sure it is writing in form of a will so that if the person is no longer of this world it can be transferred to your wife or kids because I won't even advice anyone to actually to trust a woman with there funds so they won't make the mistake of running away with your funds because the nature of women can not be understood some times, so men have to be careful.