A multisig address will protect your from the "$5 wrench" attack.  If you use a 2 of 3 multisig address you keep one yourself, give one to you mom and then put a third in a safety deposit box.

That way if you die your mom can get the safety deposit box and access your coins, you can still access your coins without your mom by going to your safety deposit box or you can just send a transaction to you mom for approval (because, yeah, you mom always needs to approve your spending anyway ).