I Thought He Was Just Being Lazy

My husband hasn't been helping out much with the kids. He's been sleeping a lot more than usual. The second he gets home from work he goes to sleep all day or he will ly down because he doesn't feel good. Yesterday I told him I needed a break and left him with the kids for less than 30 minutes and my daughter calls me telling me daddy fainted. So I drive home. He swears up and down he's okay he just got light headed. Then today he was heading to the bathroom and fainted again in front of me. He keeps saying hes sure hes fine. I thought he was just being lazy but no I'm worried something may actually be wrong.