full access on perticular folder

[Sadananda B Rai]

Hello All,
        As I am new to Linux, I need some help on sudo. I am using sudo and
it's working fine. Right now I have one user called "rai" who can do
anything as root using sudo.
        But, This user work full time only on his home folder and /var, I
want something like he can run all the commands as root only in /var/* and
he should not be able to run anywhere else as sudo. Sudo should allow
commands as root only in /var/*. I tried googling but didn't get more on
this. Is anybody can help me or is if my concept is wrong any other
suggestions appreciated. Thanks in advance

Rai