What has he done with the money? Have you filed the last will with the probate court? Has the court named you as co-executors? If so, can one of you sign or are you both required to sign? If nothing has been done this is your first step to take and do it today.
The bank should not have released the money without an original letter from the court. A copy of the will is not sufficient. There needs to be an estate account and all the money needs to be placed in that account.
Unless he does so, you can ask the court to remove him as an executor. If there are sufficient assets, the money can be deducted from his share.
Put everything in writing CRRR so you have proof. If there are not enough assets, you can sue the bank. The longer you wait the worse it will get and do not let him make you feel sorry for him. Expect him to try and keep putting you off by blowing smoke.
You can't prosecute, the police will not get involved. You are on your own two feet.