VPN subnet mask problem

[Bill]

I set up a vpn connection with my brother (xp pro to xp
pro)and it connects like it should with a pptp, but I can
not see anything on his computer. I do a IPCONFIG and
with the vpn connection I have a
ip address of 192.168.0.xx
subnet mask 255.255.255.255
Gateway 0.0.0.0.0
DNS server is corrrect with his system
I assume is assigned from his computer for that local
network but subnet mask of 255.255.255.255. is not
255.255.255.0. which is what it should be for that local
network I think this is the problem but don't know how to
fix it.
What do you think??