the pups were born yesterday and one of the pups does not suck as hard as the other pups can i help him by feeding him from bottle but still keep him with mum?

Have the pups been checked over by a vet for Cleft Palate?  This is usually a sign when they can't suckle, hopefully it's not that but something worth checking out.

Is the pup putting on weight ?  I wouldn't start trying to help him with the bottle unless he is not putting on any weight.

I took them to the vets and he did have cleft palate he had to be pts, im gutted he was stunning

I'm so sorry RIP little one

So sorry to hear that. :-(

Im so sorry to hear of your loss of a puppy. My bitch had a litter of 7 on 25th May, her first born son was quite small and he didnt suckle well, and all the others were pushing him out of the way.  I bottle fed him for 48 hrs and he yawned and i saw the roof of his mouth had not fused properly and there was a hole at the front.  I phoned the vet and 3.00am and said I thought he had a cleft palate and he was pts 8.30am. They cant get a vacuum on the teat.  Even though I was bottle feeding him drop by drop, quite a lot of the milk was coming back through his nose. He was perfect, such a cruel world isnt it.    
Gizmo is buried under the apple tree in our garden in a teak wooden box.  All his brothers and sisters (apart from one who is waiting for his new owners to return from holiday) have gone to their new homes, so little Gizmo will stay with us forever.  Its amazing to think how much love you feel for something so tiny and young.