Question about an offer to buy rights

Hello all, My elderly Father has a tiny portion of some gas royalties in West Texas, like .0000313 tiny. This has paid him around $10 per check, I don’t know if it’s monthly or qaurterly. Periodically he gets an offer to sell his share, the current one is from Oak Tree Minaerals offering him $600. In the past I told him to ignore it and see what happens but nothing has changed in a decade. He wants to take the $600, I can’t say I blame him.

I appreciate any advice those in the know could offer. Thanks!

Post the county, block, abstract and section to see if there is pending activity in the area. Many times offers to buy come right before drilling and start out low ball.

This is the info I have

Altura Energy LTD .000033 RI G1 Levelland Unit Tract 100 LSE# 4620 A-149 NW/PT 44.280 AC

They have offered to buy it several times but I had him ignore it hoping something was going to happen but nothing has changed.

Thanks!