My DS likes to have a loaded fork but also still uses his fingers.
Sometimes I encourage him to stab his own food which he rarely manages (but does show an interest to try since I encouraged a little) and if he is trying I leave him to it until he either hands me the fork or shows in some way he would like help. The encouragement was/is verbal and hand over hand but literally one or two stabs in a meal, not every meal and not forcing him. For DS it made him realise that HE can do it, same as when he used to think it was my job to hold the sippy cup until I told him he could do it and showed with some hand over hand.
I sometimes do a little hand over hand on both knife and fork to chop up one item on his plate (I stand behind him) or to spread some pate on a cracker, just to introduce the idea.
With the fork he likes me doing the 'stab stab stab' words
That said, I wouldn't worry about it. It's like any of their new skills it will come in time with some demonstration and when they are ready.
One thing - does he have a fork like yours or a plastic one or child one? I found DS didn't even recognise plastic cutlery, he has the metal ones that look like regular cutlery but are slightly smaller and the knife is kind of blunt.
