Depends what he sowed - if he sowed hardy annuals, some of those can take a while to show, specially as the weather's so unseasonably cold. If he sowed half hardy annuals, they'd need heat to germinate.

Possibly some creatures such as slugs are eating sprouting growth ?

Given how cold it has been up here I would think the seeds are just taking a long time to germinate.

Ok I will let him know before he throws them out. I know de did sow parsley, livingstone daisies & sweet peas also some lobelia & petunias

All but the parsley really need more warmth than they will get in a cold frame in Aberdeenshire right now.

Lobelia and petunia are tiny seeds and should not be covered with compost. They start out tiny but grow...eventually. Maybe best to try again?