I live in Maryland and my neighbor across the street passed away about
2 years ago.  When she died, she named my mother and a friend of the
deceased’s family (we will call him Bob) as co-executor's.  All taxes
have been paid and final distributions have been made.  I am not
exactly clear on how it was decided but the fees paid to the
co-executor’s were different.  Bobs totaled $15,000 while my mother
was paid $8,000.  Bob wasn’t going to give her anything but she
managed to get $8,000.  All documents were signed by both my mother
and Bob, however Bob claimed to deserve more because he did more work
(matter of opinion).

Also, my mother revealed that there was a safety deposit box that she
gave Bob the key to.  It managed to disappear along with its contents.

My question is 2 parts and I need you to state your sources and links.

1.)  Is Bob allowed to decide that he get a larger share of the
co-executors fee?

2.) Is what Bob did, legal in the state of Maryland, and is there any
legal actions my mother can take, for both the executors fee and the
missing safety deposit box?

Hello and thank you for your question.

1.) There are two reasons why Bob is not allowed to decide that he get
a larger share of the executors' fees.  One is because co-executors
are like partners in a partnership, and your mother is entitiled to an
equal say in deciding how much each of the executors should be paid. 
The other is because even after the executors set the fees, the matter
is subject to approval or disapproval by the Court (if all interested
persons agree on the fees in writing then court approval is not
required).

The statutory fee schedule is at
General Estate Information Guide
http://www.registers.state.md.us/html/pamphlet2.html

The Maryland Attorney General has posted a good summary of these rules
on the Internet, and I recommend that you read it closely:
Administering Estates in Maryland
http://www.registers.state.md.us/html/booklet2001.htm
The Regular Estate
http://www.registers.state.md.us/html/chapter5.htm#chapter5B1

2.) So giving the executors unequal fees is not illegal, but it is not
something Bob can do unilaterally, and if he pays himself from the
estate without the required approvals that would be illegal.  The real
illegality (if what you say can be proven) is Bob's omitting the safe
deposit contents from the probate inventory and taking them for
himself.
"The Inventory Report is the form used to report the assets held in
the decedent’s individual name or as tenants in common. Describe each
item on the Inventory Schedule in reasonable detail and indicate its
appraised gross fair market value as of the date the decedent died."
Id.

If you have a copy of the estate inventory, I think you will find that
it has been sworn to by the executors (personal representatives). If
Bob swore falsely, that is a crime.  If Bob converted (took) estate
assets for himself, that is a crime too.

Probate courts are usually informal operations.  I suggest that your
mother start by talking to the clerk about her concerns.  Chances are
the clerk will talk to the judge, and the judge will decide to do next
- - most likely inviting Bob and your Mom to the court for a chat with
the judge.  If there is an attorney for the estate, your Mom may wish
to talk to him or her first; in any event, of course, this answer is
no substitute for informed legal advice.

Let us know how it goes!

Search terms used:
Maryland probate
Maryland inventory personal representative

Good luck with this matter and thank you for letting us help.  If you
find any of this answer unclear, please request clarification.  I
would appreciate it if you would hold off on rating my answer until I
have a change to reply.