My father is a slicer. He's lefty, pushing sixty, and swings more round the body with abbreviated backswing and an over the top, out to in swing plane. I've been working with him a little to correct this slicing action first by getting more on plane and by moving the left foot back to promote a more inside out swing. It seemed to be working rather well, increase in distance, straighter shots, more confidence. Still a pronounced fade but nowhere near the banana he hit before. My question is can grip size alter your shot pattern? I seem to remember a previous post about this...

ie. larger grips would promote slice or hook?

The reason I'm asking is he's arthritic and I looked at several grips specific to that and they looked larger than the standard.

We are also looking at more friendly shafts for his swing speed but thats another thread.