I have seen those 2-room flats in my area. The quality of the tenants is no good, and that affects the surrounding 磁场. It feels like Old Age Homes, and every one who walks in and out of the elevator looks defeated.
Where do you live ? Why not consider renting out your 5-room flat and use fraction of the rental collections to rent a detached house in Johor Bahru? If your parents are not working, they can live in JB. There is still enough balance to lead a comfortable life in JB, even without contributions from your taxi business.
It's the best of both worlds. You can get keep your 5-room flat and live in a bigger landed property.