My family has been in poor health these years. Is it the geomantic problem of Yin house or Yang house?

It's possible. Both houses may cause health problems. If it's just your house, it's more likely to be a mansion. If the father and brother of the whole family, or grandparents and brothers have similar problems, a secluded house is more likely. However, if the father has only one brother, it is very likely that two people will be there at the same time.