should this be a CPS case?

I mean obviously I should call, I plan on it tomorrow. the girls are 5 and 10, but they’re from another county and IF they get taken by the state my husband and I plan on trying to foster them (they’re our nieces)but i’m not sure we can if we aren’t in the same country. and ever since the girls dad died the mom has been so incredibly mean to them. she was never a great parent imo but it’s been worse. and to top it off, she got a new boyfriend 2 days after her husband died and he was staying in the home with them. the girls are so so so traumatized. i just hope the caseworker sees what I see, they’re trained to not say what goes on in their house.

ETA: we have talked with a lawyer and he said we didn’t have enough hard evidence. i have some videos and pictures but since they don’t live here we can’t really get any proof