Pittsburg County Ok. Questions

This is a very long story but the short and to the point of it is…

My husband and his brothers and sisters inherited some oil wells in Pittsburg County Ok. He does not have any idea of how much they own, if they have been producing, or anything.

He did receive royalty checks twice several years ago, but no word since because his family does not communicate with him…

Is there a way to find out how much he owns (or owns a part of) and if it has been paying lately?? (I wouldnt put it past his family to not pay him the royalties).

Also how would we find out what its all worth? my husband just received an offer from Herv Oil but we want to kn ow more about all of this business before we decide to lease or sell…

Thank you in advance for all your help and insight.

Can anyone help me out?