A plea for help

So, because of the heart attack, my mum's been obviously off work. Which would be fine, except she's now gotten all these ideas for these projects she wants to do, and who's helping her?

Anyway, she's trying to build a family tree. Her mother's side of the family is all sorted, but she knows very little about her dad's side. He came over from Poland just before WW2, and mum thinks the rest of his family died in concentration camps.

Does anyone know of any websites or organisations where you can try to find information about these things? I know there must be places but I honestly haven't the energy to start searching myself. But I thought some of you might have tried to trace relatives.

Any help would be hugely appreciated.