Madonna's 19-year-old daughter has stepped in to mend the rift between her mother and brother.
Lourdes Leon - whose father is fitness trainer Carlos Leon - is concerned about the deteriorating relationship between the Hung Up hitmaker and 15-year-old Rocco, who is now living in London with his father Guy Ritchie, so is attempting to make piece between the pair and be a point of contact for them both.
A source told The Sun newspaper: "Lourdes is very concerned about her mother.
"Madonna has no official access or way of knowing what's going on in Rocco's life.
"She also can't get direct contact with Guy. He wants to conduct all their business through lawyers.
"Madonna is so proud of Lourdes, she believes she is proof of what a brilliant mum she was because she is now at university."
Rocco left Madonna's 'Rebel Heart' tour late last year to be with his father, stepmother Jacqui Ainsley and three half-siblings in London, and later defied a court order to return to the US to spend Christmas with his mother.
Last week, a judge ruled the teenager should stay with the Man From U.N.C.L.E.
filmmaker for the time being in order to prevent his schooling from being disrupted, and the former couple have been advised to make an amicable agreement over custody of the youngster.
It was claimed at the weekend that Madonna - who also has adopted kids Mercy and David, both 10 - is resigned to Rocco living with his father permanently, but has insisted on imposing a number of conditions regarding rules, structure and security, if that is to be the case.