Is zakaah due on his money in the bank to which he does not have access?

One of the conditions of it being obligatory to pay zakaah
is that one should have full possession of the minimum amount (nisaab) and
some scholars say that he should full  control of it; money to which the
owner does not have access is not subject to zakaah because he is not in
full possession of it. 

It says in al-Mubdi‘ (2/166) concerning the conditions
of zakaah being obligatory: 

… (4) Full possession, because incomplete possession is not a
complete blessing and it [zakaah] is only due in return for a complete
blessing, because full possession refers to what he has in hand, to which no
one else has any right and he may dispose of it as he chooses and the
benefits of it all come to him. This was stated by Abu’l-Ma‘aali. End
quote. 

Based on that, if the money in the bank is not accessible to
you and you cannot withdraw it, then no zakaah is due on it, even if the
money remains in the bank for several years. It comes under the same heading
as wealth that is missing or has been stolen or taken by force. 

Shaykh al-Islam Ibn Taymiyah (may Allah have mercy on him)
said: It [zakaah] is not due on a debt owed by one who is in difficulty or
one who is taking too long to pay or the one who denies (that he owes
anything), or wealth that has been taken by force, stolen or lost, or wealth
that has been buried and its location forgotten or wealth when it is not
known who has it. This is one report from Ahmad, and it is the view favoured
by and regarded as sound by a number of his companions. It is also the view
of Abu Haneefah. End quote. 

Al-Ikhtiyaaraat, p. 146 

It is better and more on the safe side if, when taking
possession of the money even if it is after several years, to pay zakaah of
one year. 

Shaykh Ibn ‘Uthaymeen (may Allah have mercy on him) was asked
about orphans who have money in the bank and are not able to access it until
after they grow up. 

He replied: … Zakaah must be paid on the money of these
orphans who are minors, but if it is in the bank and they have no access to
it and cannot withdraw it from the bank, then they do not have to pay zakaah
during the period in which the bank withholds it, because they are not able
to make use of their money, so it is like a debt owed by one who is in
difficulty. But when they take it from the bank, they should pay zakaah for
one year only. 

End quote from Noor ‘ala al-Darb. 

And Allah knows best.