My Dad does not have a will can I nmake up a will for him . does he half to sign it Iam the power of attorney

I am not aware of any state that allows for one person under a Power Of Attorney to create a Will for another person. In any event, even if it was allowed, the Power Of Attorney document would need to specifically state the details of that power. I strongly doubt that those words are there. It may be possible for you to attend to some estate planning through a guardianship or titling of property owned in your father's name, but do not expect to be able to essentially disinherit someone or take it all for yourself. If you are an only child and your father is single, you are likely to inherit his whole estate anyway and you have much more leeway in what you do. See an experienced Texas estate lawyer right away. To Your Success, Gale Allison, Principal AttorneyAllison Firm, PLLChttp://www.theallisonfirm.comhttp://www.linkedin.com/in/galeallison.com