This is pretty close to what a French speaker would have written, but there are still a few mistakes. Remember that I am only commenting “how” you should have written, not “what”, which is irrelevant here.

Je suis is seldom used in French to give your name, unless the person you are talking to is supposed to know this name. Je m’appelle is more common.

J’ai une famille avec cinq enfants is correct, yet a bit awkward. Je suis père d’une famille de cinq enfants would be better in my opinion.

mais je n’ai maison et nouritture is incorrect. mais je n’ai ni maison, ni nourriture would be correct. Take note that maison refers to a house (quite expensive), logement would be a more generic wording (but perhaps a little too formal). Abri (shelter) works as well.

Finally, I believe ending the message by Merci. would be regarded as more polite.

Another possibility. I don’t know if there is a best way to ask:

Je m’appelle xxx. Je suis père d’une famille de cinq enfants. Je n’ai pas les ressources pour les loger et les nourrir. Pourriez-vous me venir en aide ? Merci pour votre générosité.