SOB means short of breath. It sounds like he may need some supplemental O2, if his O2 sats fall below 88, so you should ask about that. Also ask about pulmonary rehab, because both you and he could attend the classes and learn a lot about COPD and what might be going on with him. It sounds as though his lungs have really elongated, and he may be retaining CO2. Ask about that, as well. Talk about his eating habits; there might be something there that could help.

I am thin too,need water pills for my stomach,which blocks my breathing.IT works for me in a day

Sounds a lot like my symptoms. Dr's really haven't given me answers either. But Symbicort has helped and duoneb 2 or 3 times a day helps too.

Please ,follow doctors advise please please exercise an please change ur diet , if you eat fat foods,over eat or don't exercise , you don't strengthen your lungs or heart ,ask dietien for advise an you will see a difference always build up an keep going little by little an breath deep an push on never surrender, never give up it's a man thing lol

Being SOB does not relate directly with blood oxygen level. Ask your pulmo to explain why he gets SOB when his O2 level is 93 It can sure happen.