The Official Roll of the Baronetage now shows the von Friesendorff Baronetcy as being vacant so the 11th Baronet must have died recently. I have not been able to find anything on the internet at the moment.
Baron Sir Rickard Fredrick Knut von Friesendorff, 11th Baronet succeeded his father Baron Sir Claes Fredrik Wilhelm von Friesendorff, 10th Baronet in 1974 though he did not establish his claim (after the baronetcy had long been dormant) until 2018. He m (1) 1965 (div 1972) Siv Monica ERIKSSON and (2) 1986 Eva Birgitta NEILRU. He is succeeded by his only legitimate son (his other son being adopted):
Baron Sir Johan Fredrik von Friesendorff, 12th Baronet (though yet to prove his claim) b 1966 m 1995 Maud Charlotte JOHANSSON and they have issue:-
Baron Carl Adam Fredrik b 1993
Baron DAVID JOHAN b 1996 (twin) (ha)
Baron Rickard Ragnar b 1996 (twin)