BOAC using an FTP server is not really an option, you would have to download the mdb update it and then re-upload it.
I would suggest to your son to download SQLServer express edition, as gertrude says you will be able to redirect the front end to it quite easily. There are also upsizing wizards available and plenty of reference material available (
How do I upsize from Access to SQL Server?).
SQL Server Express edition is free but will limit your database to 4gb in size - if your project takes off you can buy a licence for SQL Server and get the full edition without restriction (No changes required to access front end).
If you have downloaded SQLServer express you only need to look at using the "Link External Tables" option and the rest of the development is pretty much the same. Feel free to PM me if you want more info on SQL Server or if you have any problems (Saab if its of benefit to the forum will paste any answers here also).