You have a person who's on the road without Internet access, and you want him to have access to a database that's at the office without being connected.
The only way I could see simplifying this is to do a nightly dump of the database, then create a batch file or powershell script that he can run from his laptop when connected to a secured shared drive with that SQL dump that will import it into his local copy of the database.
He'll always be behind in what information is available, but your constraints effectively require him to not be in sync, and there's no way I know of to automagically replicate to his laptop when it just sees him. Not without creating some really roundabout scripting that detects when he logs in and does a dump and import of the database each time.
You don't say what's in the database, but if it's small enough you could do hourly database dumps to that directory and delete dumps of a few hours old, so he can grab one that's more up to date than once a night.
There's no way with these requirements that it's not going to be kludgey and not-so-pretty...
If you're having him change things on his laptop and you want it into the other database, then you'd reverse this.
If you're making changes on both databases,...I'm not sure that can be easily done. You'd essentially be describing what happens with a database cluster that is constantly hitting a split-brain situation. You would need to combine the "log in with cached credentials" answer (don't log in locally to the laptop) with research into setting up and licensing SQL server (Is it MSSQL?) or configuring MySQL or whatever you're using as a cluster that looks for his laptop, and how to resolve split brain errors in a cluster so it periodically resyncs with his laptop. But this will be asking, in my opinion, for possible errors and management headaches, as I've not heard of anyone trying something quite like intentionally keeping part of a cluster offline all the time, plus it will give you a lot of errors in the logs as your cluster will be "broken" all the time.