Is it unusual if my husband has slept since we got home?

He will wake up but then go right back to sleep. He naps quite often during the day, but when should I become concerned? When he naps, he really naps. He is fully functional, and sometimes he isn't asleep, just with his eyes shut but not asleep-resting. We got home around 4:30 pm and it is now 8:10 pm. We had pizza for supper, which he woke up for. And now he is sleeping again. I don't know if this much sleep affects his sleep at night. He does have major heart issues, and icd, copd and emphysemia. He is 82. I'm not feeling real worried right now. He just is sleeping alot!