He should be sure to exfoliate often so that the skin is smooth. Then it´s really important that the shaver is sharp and the "thing" protecting the blades have to be completely without any damage. On most shavers you have to change the "head" almost every year.
Also bad shavers tend to do this, when they are not sharp enough you press it to hard against the skin witch irritates the skin. My BF had the fortune to find a cheap one that is good, but most of the times you have to spend a lot on the shaver. That shaver has done a huge improvement in his skin.
With some electric shavers you can use shaving cream, maybe that will help, but I think just using it on wet skin (without cream/foam) would irritate more.
//Jenny