Hindsight's 20/20

a few years ago my dad lost his job... "move down here, there are jobs here... come stay with us..." I offered, it was the least I felt I could do. We had a good relationship, he and Hubs got along (drinking buddies, in fact) and there would be someone at home with me because his schedule was the same as mine and my schedule has always been the opposite of Hubs' schedule.
Fast forward through the next two years. Dad stayed with us for the first year. Never paid a penny for rent or utilities, I never asked him too. He held multiple jobs. None of them were quite what he wanted. He would stay most evenings with his ex-girlfriend and their daughter, until the daughter would go to bed, then he'd come here to sleep. Until he stopped staying here, he would come pick up a few of his clothes and go spend a few weeks with them. (They moved down when he did and live in a neighboring town) Then he stopped coming over all together, stopped calling. He got a job that included training that would keep him away for several months. He finished the training, got certified, and quit.
In September 2009 I found out that I am pregnant. He hasn't been here in almost two years. The room that he slept in still holds all his stuff, ie bed, dresser, clothes, tv, movies...
In October 2009, I call him, Dad - I just found out I'm pregnant, we're gonna be needing the bedroom that your things are in for the baby. Do you think you could come get it? Sure, no problem.
Almost a month goes by before I hear from him again. He texted me... Do you think I could come stay with you? Until I can find a job back home? My dreaded reply.. Sure, are you working now? He apparently was working, but didn't know how long it would last and said he wanted to find work where we are originally from. He comes home that Sunday, bringing things to prepare his lunch with for the week.
The next two months would be interesting... During the week, He would come home after my kids and I had gone to bed. And on the weekend, he wouldn't come home until Sunday around 8PM.
He has habits that I don't approve of... one of them being he smokes. But I don't mention anything to him about it, except for the request that he do that outside and never in the house. On the other hand, my kids have mentioned it to him or said something in passing. The 13 year old has really only said something to me... smoking really bothers his asthma. But the four year old, well, you know how four year olds can be... "Paw Paw, cigarettes is nasty!" and things like that to him. And mostly questions like "Why do Paw Paw's smoke?" to me. (Both her Paw Paw's smoke) Now as I've told friends with these questions, I'm not going to beg her not to smoke, tell her it's nasty and then turn around and reprimand her for telling him that. I believe that would be couterproductive on my part.
December 2009. He text me on the 18th after he'd left home for the day. Not sure at this point if he'd been working or not. "Have a good doctor's appointment, Happy Birthday" (He found out about the dr appt from Facebook, he's on my friends list) After the 18th I didn't hear anything from him...until January 1st at 3:30pm.. he texted me "Happy New Year, I love ya" and nothing since.
It's been a little upsetting, it's been strange, it's even been mind boggling... but I really don't know what to think of him... and I feel that my family and I have been used. And I really hate that it was by my own dad.