Lincoln is officially a big brother! Javi Marroquin and Kailyn Lowry‘s son, 3, just met his one-week-old brother a few days ago, and he’s already adjusting to his new role. The Teen Mom 2 star and father-of-one revealed exclusively to In Touch that his son is “excited” to have a new playmate.

Javi — who is a member of the United States Air Force — exclusively told In Touch, “Lincoln knows he has a new baby brother. Like all kids, they are excited to have a new sibling. I have to remember now I have to say ‘brothers’ now instead of just Isaac.” Kailyn gave birth to her third son with her third baby daddy, Chris Lopez on Aug. 4. and she shares Isaac, 7, with ex-boyfriend Jo Rivera.

MORE: Kailyn Lowry Hopes Baby Daddy Chris Lopez Changes His Mind So She Doesn’t Have to Be a Single Mom

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Controversy has surrounded “Baby Lo” since Kail announced her pregnancy back in February. One of the most dramatic components was in regards to whether or not Javi was the legal father of the newborn. He told In Touch, “Everything should be taken care of on the legalities of the new baby, I’m pretty sure.” Uh oh, that doesn’t sound too convincing! Luckily, according to lawyer Brooke Camhi, “[Their home state] Delaware law states that the ex-husband is presumed [to be] the father of a child if the child is born less than 300 days after the divorce.” Considering that the two split last year, Javi should be in the clear. Phew!

Yet despite all the drama, the father-of-one, 24, is being mature. “Whatever issues Kail and I had cannot impact Linc’s relationship with his new brother. So I do make him excited about it.” Ugh, he is the best dad!

Teen Mom 2 airs Mondays at 9 p.m. EST on MTV.

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Scroll through the gallery below for photos of Javi and Kail’s tumultuous relationship!