This confirms the first post. My bro called and got this info:
1. An expired Singapore license cannot be renewed after 3 years,
2. You have to apply to convert your US/Foreign License to Singapore License,
3. You need to take the Basic Theory Test (BTT) administered by the couple of driving schools in Singapore,
4. Have to apply for the BTT in person and waiting time is approx 4 weeks. The Traffic Police lady said you can seek the respective Chief Tester at the driving schools to allow a shorter wait time. But for sure the driving school would need you to take a couple of their Lessons before taking the BTT,
5. As for the full class 2, you would need to show proof that you had owned a big CC bike for the past 3 years. Such proof could include registration papers or insurance certificates etc.
This will apply to anyone who has never had a Singapore license, expired Singapore license or has obtained a foreign license while overseas.
Hope this helps others with the same issues. Thanks to my bro for doing this.