Actually, Southwest does offer international redemptions for credit card holders. It looks like they price based on the revenue cost. A quick search on a random date in April found a LAX-PEK one-way for as low as 52K (though many other choices were higher). That could possibly be combined with a one-way award on another airline (e.g. AA) to build a roundtrip with the existing WN miles and whatever new miles he collects (or with a paid one way).