Hi there. There can be lot of reasons where bleeding of gums is noticed, most common of them being gum problems. Most likely, your husband is suffering from Gingivitis, which is a condition with inflammation of gums. There are lot of factors leading to this, poor oral hygiene being the commonest.
Next Steps
Please visit a dentist for a full mouth cleaning and polishing. Along with this, he should start brushing thoroughly twice a day, warm saline gargles twice a day and gum massaging with firm pressure.
Health Tips
Do get scaling done every 6 months. He will definitely get better if he follows all these instructions properly. Just like we need to brush everyday, we need to get our teeth cleaned every 6 months...Hope this helps :)