suddenly aggressive 7 yr old golden

Question
My golden (who I have had from birth) recently became extremely aggressive.  He has bitten me twice, the last time requiring hospitalization. I retired from my full time job and  within 3 weeks I started to see personality changes.
Our female golden pasted away a year ago and we adopted two other goldens who he seemed to accept.  Upon my retirement he has chosen to challenge our young male constantly. The young male does not charge at him or do anything suddenly. It seems that Riley just gets angry when the young golden (Mason) is around me.  He also had an episode a few days ago  when we were walking.  He took a run at a young man on a bicycle. He grabbed him at the knee. Riley has never had any negative situations with bicycles.  
I have changed his food, had him to a whisper, put him on Essential oils and Floral Essences and pray for him to become the friendly soul he used to be....

What else can I do

Answer
Hi Sandy.

It seems that Randy is being over protective of his position in the pack(family) I suggest you get him neutered. As for the aggresivness, you probably will need to see a professional trainer to solve this. I can't do anything over the internet. Until then, keep them both away from each other, especially when Randy is eating food or chewing on a bone.