My 2 yo son was diagnosed with asthma, should I start having him take swimming classes? Can you recommend good coaches/swim schools in Alabang?

yes! Swimming lessons should start as early as possible. I think it's best if you try enrolling him to Bert Lozada's swimming lessons. Here's their website for your preferred location: http://www.bertlozadaswimschool.com/locations

Check Bert Lozada swimming school. http://www.bertlozadaswimschool.com/muntinlupa