Yes, that is correct. Time dilation, as predicted by Einstein's theory of relativity, suggests that time can pass differently for objects in relative motion or different gravitational fields. When traveling at speeds close to the speed of light or in the vicinity of a massive object, time dilation effects become significant.
If colonists were to embark on a journey to a planet located more than 50 light-years away from Earth, and they traveled at a speed close to the speed of light, significant time dilation would occur. As a result, while the colonists may experience only a few years or decades of subjective time during their journey, several decades, centuries, or even millennia could pass on Earth.
If enough time has passed during their journey, it is indeed possible that the colonists may never see their family or loved ones on Earth again. From the perspective of the colonists, their family members on Earth would have aged and potentially died due to the passage of time. It's a consequence of the time dilation effect and the vast distances involved in interstellar travel.
However, it's worth noting that this scenario assumes near-light-speed travel and significant time dilation. In reality, the technology required for such interstellar travel is purely speculative at this point, and the feasibility and practicality of achieving near-light-speed travel remains uncertain.