I am using 7.4.2

When I click on the "send password" button it sends the user a temporary password. Is there a way to have it send them their current password?

No, But remember the temporary password does not change the original password. And if they finally remember it the next day it will still work
So once the user has logged on they can continue to use the temporary password or open their profile and type a new one.

Passwords are stored in the UBB.Threads7 database as an MD5 hash; MD5 is a "one way" encoding; as such, there is no way to "decypher" the password.

Hence why a new temporary password is sent and they need to set a new password after that.