My question involves criminal law for the state of: Texas

New to the site. Trying to find out if there is any way possible to get a sentence reduction for my husband. He was sentenced in 2007 for possession with intent to deliver meth 4-200 grams & received 25 years TDCJ. His attorney did not file his appeal on time & now he cannot get an appeal. My question is: Is there anything that I or he can do to get his sentence reduced. I thought about writing has judge or the governor, or writing up a petition but I actually have no idea what to do or where to start. Any ideas would be greatly appreciated. Thanks