can you wait to put him to bed until after he pees?

apparentlky the motherease sandys nappies are great for heavy wettesr. I"ve never tried them though. for covers, you can't go past a zappy nappy pul cover. they aren't very common - get them from nature's child - but the shape of them and the elastic is much less likely to wick.

keep an eye on his wetting patterns, he may have just wet just before you get up to him, in which case at least he hasn't been sitting in it all night.