poly also comes in a low loft. it doesn't have to be overwhelmingly puffy. even the low loft is fluffier than w & n.
does he like a heavier weight or a lighter weight? that's a difference, too.

machine stitching through a high loft poly can be hard. it's very easy to get puckers if you don't baste it or pin it a LOT. will you be LAing or domestic machining?

I use 80/20 hobbs and it is great I get alittle quilt shrinkage that I call puffy. your talking about comforter and you would want a high loft poly

Since 1972 I've made tied quilts with high loft poly. Most of them are still around and drape beautifully, despite hard use and frequent washing.

Some of the quilts I made when I first started quilting have had the batting bunch up. Of course I don't know what I used, but I think it was poly. They are quilted very close probably no more that 4-5 inches. I prefer cotton and I like the scrunched up look when it shrinks. Makes the quilt look old.
Sue

I just took a bicentennial 1976 quilt out of the closet for a look recently. It was made by my MIL and has a poly batt which is bearding in many, many places. I wonder if the newer poly batts beard. You also never want to touch an iron to the quilt with poly batting as it becomes flat. I found out the hard way when pressing the binding over the edge of the quilt.

I prefer wool batting for loft and the trapunto look without the work of trapunto. It doesn't melt!

The 1976 quilt was hand quilted, and now has many broken stitches. We used this quilt for probably 15 years, and I never noticed what had happened to the thread. It is so sad to see this after so much work was put into this quilt.

I have used a polyester batted quilt since I first made it in 1980.It is on my bed every day and has been washed many times and still looks in very good condition.

This is what I use most of the time, always presoak it and it's lightweight, soft, warm and comfy. Haven't come across Hobbs PolyDown but want to try it. Quilter's Dream has great batting, a little more expensive but worth it. Not a fan of W&N as I don't like the 'old fashion' look after the quilt is washed. Kid and Baby quilts always get poly, they get washed at lot.

First quilts I made for DGrandkids was over 10 years ago, they had the cheapest poly batting and very little quilting and they have held up without any bunching of batting.

I use the extra loft poly batting for everything except wall hangings and for them I use a thin pellon. I have never had a problem using extra loft and I like the puffy look.

I made a huge king size quilt using black fabric & the poly batting bearded on me. I worked so hard on it & just broke my heart. I don't use straight poly anymore.

Just my opinion.
I am a nurse and usually people sleep best with natural fibers. Polyester does not "breath" as well as natural fibers. Waking up during the night too hot or sweaty may possibly be fixed by changing bed linens to natural fibers.

That being said, if the quilt is for back of the sofa or wall hanging then poly is fine, but if the quilt is for sleeping under then I would recommend cotton.