I'm an rt. My pt. Has 50% lung function and severe copd. What are the recommended medications?

ICS, bronchodilators. For maintenance medications, the goal is symptom relief. This can be done with bronchodilators ie short or long acting beta agonists, ( albuterol, formoterol) and anti cholinergics, there is some atrovent (ipratropium) may increase the risk of cardiac events, so long acting anti- ach drugs like spirva are better. Inhaled steroids may be lower the risk of COPD exacerbation's as well. ( torch study) and are used.
A few suggestions. LABA/LAMA/Steroids are used to treat COPD, but I would add that other causes of obstruction and/or restriction can be investigated. A DLCO and lung function test including volumes will add more information.