Solid Snake.
Snake has had an array background which chronicles his experience with love and war. His children might live someday in a dreaded warzone. Think about how his children can live in an environment which is unsafe. Snake has all the abilities he can make by teaching them how to do self-defense and take action when necessary. Snake may not be a kung-fu artist, but he can sure trust his children to go out in the world with his unique skills in knocking people out temporarily and having his children safe from harm.
Snake may handle guns, explosives, and rocket launchers, but that is in no way of reach for the children. Snake can teach his own kids that not to handle such dangerous weapons at such a young age. Who knows if they will find a gun or a knife and start playing with them and get seriously injured? Since Snake has the experience with all of that stuff, he makes sure all of the weapons will not be seen by his children.
When Snake sends his children to school, he makes sure he gives them cellular devices beforehand to call Snake in case of an emergency. He also gives out a special notification to the principal there that they are allowed to have cardboard boxes hidden in their backpacks in case some bullies want to try and find them. Given Snake's excellent stealth techniques inside a cardboard box, the principal makes an exception and allows his children to bring their unique cardboard box to school. Whenever bullies try to hunt them down, they can sneak inside a cardboard box and find a safe place where no one can see and hurt them. It's very convienient and wise for Snake's children!
After school ends, Snake's children come home from school. Now if some cheap unfortunate losers try to hurt them in anyway, they can just call Snake and say "DADDY! DADDY! SOME LOSERS JUST TRIED TO GO AFTER ME! CAN YOU PLEASE COME OVER HERE AND KICK THEIR BUTT?". Certainly, Snake knows where his children are behind his back. With no second thought, he just comes out of his door, runs like mad, and sees the losers. As soon as the losers try to come after Snake's children....
This pops up over their heads. As soon as they see Snake, they try to go and hurt him. Snake quickly comes behind them and puts them in a chokehold and pins them to the ground. He then takes his children home from there. Who knew such a great father can take care of your children like that?
As they become adults, the dangers of the outside world get even greater. They will have to start navigating cities, looking for jobs, and start becoming supportive of their own. They can not rely on their dad, Solid Snake, to do their dirty work for them. Snake teaches them the importance of hiding away from criminals and if necessary, teach them fighting lessons. This way, they can be safe in the outside world and not having to use weapons as their last option. As seen in MGS: Twin Snakes, Snake can do all sorts of amazing actions, like dodging a missle. What important affect can this have on their children? It's knowing the advanced techniques of being fast-paced and getting away from dangers as soon as possible.
Snake's children will eventually grow up and get married someday. His children wants to find the perfect match and Snake can help them out. As seen in MGS1, Snake has had a relationship with Meryl Silverburg. The important success that Snake would teach his children is not to go too fast with them, such as using cheap "pick-up" lines. Another important thing would be to develop a bond with them for a long time just like Snake had with Meryl. Always sticking close by with their match is the perfect thing to do and have them get married.
In conclusion, Snake possesses a great deal of experience he received throughout his adventures and he will pass it on to his children so someday they can look up to their father and say "I have the greatest father ever, he has taught me such a great deal of experience that I can never forget". Whether he is in the battlefield or when he is at home, Snake will always remember his children and make sure they are well taken care of. Solid Snake is the perfect video game character to be the best father anyone could ever have.