Gaining citizenship in the US

Native Texan here and I’m at a complete loss of where to even begin to ask for advice, a close family friend lives here in Texas and I’ve known him and his wife for 7 years. He’s been here since he was two his mom brought him here and his dad passed away in the process of trying to get to Texas. With that being said I can go on and on about how hard of a worker he is and how he is married to someone how was born in America just like her parents and so on and so forth. My question is they’ve lived in the Houston area their whole life and has gone to 5 lawyers with no luck he files taxes every year and works as many hours as he can and he’s just a blessing to those around him and they’ve exhausted all options and it’s hard to keep paying lawyers that give no answers in this economy and with not having a green card he has to get paid under the table and isn’t making as much as he should. Is there any advise anyone has for this situation or what to do?