“What medications are best for the treatment of asthma?”

Inhaled steroid for daily use and bronchodilator for as needed use.

There are many medications to treat asthma and what should be used really depends on how bad his asthma is. It is very important to control asthma symptoms as poor control can result in complications later in life. You should discuss his specific condition with his pediatrician and he may benefit from referral to a lung specialist.
Good luck! Take care!