Relax. While a lung function of 25% does put him in the very severe range, there are medications and treatments that are available. The first thing I'd ask about is supplemental O2. The standards in the UK are different than here, but it would be worth getting an oximeter (order form Amazon if you can't find one in a pharmacy) and see what his O2 saturation levels are when he does various things. If it's under 90, talk with the docs and see if you can't get him O2. That will help him because he'll be able to actually exercise and get stronger. Aerobic exercise: shoot for 30 minutes a day with no stops, so start as slow as you can and work up. O2 will help with this because he's be able to continue even if he's really short of breath. Weights/resistance: at least three times a week for upper, lower and core muscles groups. Especially the legs: lunges and squats are critical.

Understand that exhaling is way more important that inhaling. He'll inhale just fine; what he has trouble doing is blowing off the CO2 that builds up. That's what makes him short of breath. He needs to learn Pursed Lip breathing; google it and you'll find descriptions and videos. He need to practice it until he breathes that way automatically.

Learn about COPD. Here's a really good series of videos that will teach you a lot. Watch them with him and talk about them. https://www.copdfoundation.org/Learn-More/Educa...

All the best!

@TZ000

Have docs review grandfather's med list. Sometimes being g on meds a long time can be trouble. I had a night cough, and being a nurse, one bite it occurred to me to ask about my blood pressure med, lisinopril/hctz.

It is one of those meds. We changed, and cough has resolved.

There could be a combination of things involved.

Keep up your labor of love and best wishes for your studies for paramedics positions.

He is lucky to have you.

Blessings and prayers and hugs for all.

Vicky

Pets, dander , allergies to food. Dust and mess can cause problems. Talk with pulmonologist.