On Sunday, rapper and co-founder of Cash Money Records Birdman wished fellow rapper Lil Wayne a happy 33rd birthday. While it may seem like a nice gesture, the former friends and business associates are embroiled in a $51 million lawsuit that Wayne slapped Birdman with in January.

In the Sunday Instagram post featuring a picture of Wayne, Birdman wrote, "Happy BDAY to my son #tunechi #ymcmb4life blatt."

A photo posted by Birdman5star (@birdman5star) on Sep 27, 2015 at 5:21pm PDT

Some fans speculate the record producer called Wayne his son as a way of maintaining that nothing can sever their ties. Wayne has called himself a "prisoner" of Cash Money Records and desperately wants out of his contract.

Tunechi has not responded to the birthday wish publicly. It doesn't seem likely that father and son will reconcile.

Weezy celebrated his birthday at a time of personal and financial stress, due in part to the pending $51 million lawsuit against his former mentor, who doesn't want to let the New Orleans rhymer go. His "Tha Carter III" album was the only hip-hop record to sell a million copies in one week, and Birdman wants to cash in on future success.

Meanwhile, the "Hollyweezy" rapper recently lost a lawsuit with private jet company Signature Group. The company claimed that he signed a 3-year deal, but didn't pay for two years. Wayne denied signing a contract, but the judge disagreed. Now, Weezy must make good on the missed payments, late fees and attorney fees, which will cost him roughly $2 million.

Wayne's Young Money Entertainment has also been sued by Tickets of America and White Glove International, who claim the rapper never paid for $119,400 worth of tickets, including a front row seat at the boxing match between Floyd Mayweather and Manny Pacquiao.

TMZ reported last week that there is also a sex tape featuring Weezy and two unidentified women being shopped to porn companies. The rapper is reportedly terrified about its release because he's wearing socks in the explicit footage-- something that sources say he is embarrassed about.

Wayne's representative told TMZ that, if there is a tape, the rapper didn't know he was being filmed. The representative threatened legal action if the tape goes public, saying, "We'll sue the hell out of them."

It seems the only good thing happening for Wayne is a continued friendship and work relationship with former girlfriend Christina Milian.

Nearly two weeks ago, following a year of dating, Wayne and the singer broke up. Milian released her first single, "Do It," a love song featuring Weezy.

In the video clip below from a recent interview with Entertainment Tonight, Milian said that she and Wayne have remained amicable and will shoot the "Do It" music video together in Miami.