DNA

How can i get a dna match on someone who is not related to me . but only as a connection with my mother as she and this Jerry nilsson  -  have a son together see here how i mean i    → Barbro Anita Ågren your mother → Jerry Nilsson here ex-partner → Edvin Ragnvald Magnus Nilsson his foster father → Marta Carolina Nilsson his sister → Oskar Otto Petrus Backman her husband → Jonas Petter Backman his father → Karl Johan Backman his father → Jonas Backman his father → Catharina Elisabeth Örbom his mother → Margareta Fredrika Örbom her sister → Anna Dorotea Meijerberg her daughter → Johan Lundblad her son → Ida Lundblad his daughter → Hjalmar Johansson her son → Yngve Johansson his son → <private> Persson (Johansson) his daughter → Persson her husband → John Persson his father → Anna Katarina his mother → Anders Mikaelsson her father → Brita Margareta Mikaelsdotter his sister → Harald Forsberg her son → Lilly Henriksson his daughter → Folke Henriksson her husband