Husband is having a hard time breathing especially lying down

Husband is 46, diabetic 20+ yrs, dr gave nat-oseltamivir 75mg n tyl 500 mg on Wed for flu. Plus flu symptoms, he’s having a hard time breathing especially lying down. He woke me up 5 am this morn, he said he was sitting up and “idk, I fell over”. He fell to the floor. Flu can be treated at home but at what point do i take him to the hospital?