Thank you all for your comments I will certainley take them on board, and hopefully things will improve.

I agree with all the mums here. We grandparents should not interfere unless asked. If he is rude to you then you can tell him you don't like the way he is talking to you. Just carry on being friendly with your gs and be there for your daughter if she needs you. A grandparent/grandchild relationship is too precious to be falling out about things that don't seem to be bothering your daughter.

As the mother of a similarly mouthy child, I'm sure that she thinks she's doing the right thing and helping these children is alot of trial and error. If your mother had told you how to raise your children do you think that you would have listened or wanted to learn yourself? I'm sure a simple "I don't like the way you are speaking to me" may help????? Teenagers will be rude to impress their friends, he needs encouragement to not be a lemming.

If you don't like the way he talks to you then you have the right to say/do something about it.

If you don't like the way he talks to your DD then you don't (unless she asks you to). She is doing her parenting her way based on what she thinks is important.

Sounds like normal (if unacceptable) showing off in front of friends. Show him when you're pleased with him - whether he'll admit it or not, he'll want you to be proud of him. Support your daughter when she shows or says she is unhappy with his behaviour. Really not sure what more you can do to be honest.

It seems that he thinks its good to be rude to anyone when he is in front of his friends and sometimes he can behave really well.

It is hard I think to stand back when you see unreasonable behaviour from your gs, knowing that you would deal with it differently.
I know my father feels my ds should be given a clip round the ear if he is rude or has a strop when thwarted/frustrated, but I don't agree with that and prefer to do things my way.
My dad still comments (he can't help himself) but I know he's not commenting on my skills, rather on the way he would do things.
Does he behave towards you in a way that's disrespectful?

(and resist saying "I told you so" if it does get out of hand and she needs your help! Just be there for her)
You sound like a wonderful Dad and Grandad, you make me wish mine was still around. He'd be saying exactly the same thing as you about my DS and you could have had a good chat about it together!

You love your dd and dgs and you obviously want what's best for them.

You said you have told your dd but she doesn't think it's a problem.

So you have to leave it. Your dd needs to bring up her children as she sees fit. You brought her up as you saw fit and now it is her turn, whether you agree with it or not.

Thank you very much for your advice ladette

Perhaps you need to be careful that your DD doesn't think you're criticising her parenting. Some of us can be a bit sensitive in that respect, and it might affect your relationship with her. Maybe try praising your GS when he does/says anything nice around you. It's a difficult age, but they still do respond to praise IMO. Ignore the bad stuff unless your DD invites your help? I know it must be hard to stand on the sidelines and watch behaviour you don't like, but i don't think there's an easy answer.

he wont listen to man to man chats he thinks its all crap.I have tried but dd seems not to worry

(sorry terrible spelling there!)

i'd have a 'man to man' chat with his too as ladette suggested. my ds(14) tends to have alot of time for his grandad and will act on his advise.

What does he say?

well if she doesn't have a problem with it, then perhaps it isn't really a problem? It might not fit with the way you believe children should talk to their parents, but if it's not upsetting your DD, then I guess it's her family and her choice. If she is getting upset, then it's a different matter.

yes but that doesnt excuse the wat he speaks to her. its rubbing off on the younger one too.

HAve you got any examples?

TBH he's her son and it's her choice as to whether to let it continue or not. As hard as that may be to you. She has to bring up her children in the way she sees fit. Her ideas/rules may not be the same as yours, but they are her children.

my eld gs is nearly 12, my dd says i should not get so wound up over him as he is just expressing himself verbally "!!

how old is he? My Mum often says I shouldn't let my DCs talk to me the way they do. I don't "let" them, I tell them it's not the right way to talk to anyone, but they still do it. Perhaps a "man to man" with your GS about respect, telling him how disappointed you are might help?

does she have a prob with it? (your dd that is?)

as a gdad i am appalled at how my eld gs talks to my dd any ideas ??