How to handle taxes from life insurance stock sale? : personalfinance

My sibling and I had obtained some MetLife inventory and Brighthouse Monetary inventory in reference to a life insurance coverage coverage from a guardian passing away. We bought the inventory this 12 months and simply obtained 1099-B from every Metlife and Brighthouse Monetary.

A number of questions:

1) There isn’t any cost-basis listed. How will we determine this out? We by no means purchased the inventory instantly and no concept when the life insurance coverage coverage was arrange.

2) The 1099-B lists each me and my sibling. We’re each adults and file separate taxes, so which sibling studies the 1099-B? Or do each?

Thanks!