Son AND husband both liars????? Please help.

Hello. By way of introduction, I am married and we have 4 biological children. My oldest has Austism, and OCD. My second son has bipolar disorder (but he does not usually lie).
My oldest son is 11 and he started lying a year or so ago. He also steals compulsively. I think for him, he is having severe difficulty w/ impulse control and plan to speak to his psychiatrist about it.

On the other hand, my husband (40) ....I am starting to suspect he may be a pathological liar....not sure if this is the right forum for this question? He doesn't seem to know when he is lying...like he really believes the lies. So much so that I am not completely sure he is lying.

He is a wonderfully fun, loving, patient, and funny person. He has always been very kind to me. I love him deeply. We have a great relationship. There really is no reason to lie to me. I have always trusted him implicitly.

From the time we first met, he told me some pretty fantastic stories. They seemed unreal but several were corroborated by other people. Still others have never been corroboroated.

We have been married 12 years and only recently have I begun to suspect anything (maybe in the last year or so). Here are the odd occurances that have me wondering:

* Other people will tell me things he supposedly has said to them. They are sometimes completely out of left field and untrue, and sometimes they are enough of a variation of the truth that they are based on truth but so many details have been altered that the story is basically no longer true. When I ask him about these things, he says the other person is mistaken. He did not say that.

* I have heard him tell "white lies" on the phone...like "I am eating in my truck right now" when he is only about to eat and standing in our kitchen...or that he has tried to call someone when he hasn't, or that he has made an effort that he has not made, etc. I suspect he also does this with me. When I ask him about this he shrugs it off like it's inconsequential.

* He often says he's told me things that I am sure he never has. This makes me feel like I'm going crazy....sometimes he's right and he has told me but I was distracted and I will remember later. Sometimes I am certain he never told me.

* This past weekend I was out of town with our youngest. When I returned, my mother called and said she'd talked to him on the phone while I was gone and he'd told her about going camping w/ the kids. I asked the kids about it and NONE of them could remember going camping, cooking outside, having a campfire, NONE OF IT. When I asked my husband about it, he told me a whole story. I asked the kids about it again later, usind some of his details to spark their memories. They looked at me like I was nuts and insisted they did NOT do any of those things but in fact stayed in a hotel. He also is telling 3 differnt stories about how his cell phone was damaged.

Now, this last example has me particularly concerned because there are obvious and present witnesses to his weekend activities. The children would find camping out very memorable and would gladly tell me all about it. But they know nothing of it.

How concerned shoudl I be? What should I do???
I have also confronted him before about his "white" lying and told him howit makes me feel and that it can put me in awkward situations, and asked him not to do it. He insists he has always been truthful and it's other that are are making him seem otherwise.

I am also wondering if this is something that can be inherited??? Could my son be lying because his father lies? I know some mental health conditions can be hereditary. Is this one?

Does anyone have any advise for me????