Persuade him there are bargains to be had. We got one a couple of years ago on ebay, 2nd hand, is a real time saver for DH. Ours also shreds so well worth the £ - check out ebay for a bargain and before the leaves start to fall and everyone wants one!
We have a Black & Decker one, which you can use either as a vacuum or a blower. But if the grass is long and damp, then the leaves get really well stuck in it, and frankly I don't think it's any faster that raking. But if you keep your grass decently short and have drier weather than us, I guess there might be an advantage.
They're not too bad for weight - our one has a shoulder strap so that takes most of it anyway, and you just have to point the business end of it at the leaves and wave it back and forward over the area.
I guess if you don't think the leaves will be embedded, then a blower could work faster than a vacuum, if you could blow them all to one end of the garden, since I think the "blow" on ours seems to go further than the "suck" IYSWIM?