LINCOLN, Neb. (AP) — A tiny boy born on his parents’ way to a Nebraska hospital is struggling for life as they mourn his twin sister.

Kaleb and Savannah Clark arrived early on Feb. 5 as their parents, 39-year-old Kevin and 36-year-old Laura Clark, headed to Lincoln from their home in Barnes, Kansas.

Kevin Clark had to stop alongside U.S. Highway 77 on the south side of Lincoln because one baby already had arrived.

Laura Clark’s cousin Mary Crevier told the Lincoln Journal Star that two days after the twins were born, Savannah died after blood vessels burst in her head and lungs.

Crevier says Kaleb weighed about 2 pounds at birth. He’s since gained about 10 ounces and been taken off a breathing tube.

She says Kaleb’s “a little fighter.”