I would be surprised if your music were forgotten when you are gone, nigel.
my dad often comments that my mum never found out who her "real" dad was ,only finding out late in life that the man she knew as dad was not so, biologically.
I usually comment that the man who done the job was the "real" dad.
in similar way ,whether the biological father is still around or not, I am sure you are to all practical purposes ,dad and granddad by being the loving supportive person you are. blessings pete.