The short answer
If your LDL is 190 or higher, or heart disease came early in your family, yes: parents, brothers, sisters and children.
Familial hypercholesterolemia is passed down, and each child of a parent with it has a 1 in 2 chance. Children with FH can be checked from about age 2. If your Lp(a) is high, relatives should check theirs once too.
Source: European Atherosclerosis Society FH consensus, Eur Heart J 2013; 2018 AHA/ACC cholesterol guideline.