Legal Question in Family Law in Texas

Probably not. There is no way to overturn a court order because one party chose not to hire counsel. If there is a defect in the decree or the litigation process then maybe your friend can pursue a motion for new trial and/or appeal to overturn the decree. If your friend is serious about this path he needs to talk to an attorney ASAP because there is a very limited time frame in which either approach may be pursued.