Jay (anonymous)

I opened a joint brokerage account with my mom & dad. I am 57, my mom & dad are both around 78 years old. The contribution to the account is solely my money. The account was opened as “joint tenant with right of survivorship” to pass on the assets to them if something happens to me as I am their only child. I want them to have some money in case nobody else from my family takes care of them after I pass away.
I do some trading in that account so that there is some capital gain along with dividend from that account
I understand that the income from account (dividend/interest) is to be reported by me to cra because of attribution rule
My question is about the capital gain. Do I have to divide the capital gain in 3 portions & report 1/3rd on each of our returns (me, mom & dad) ? OR can I report the whole amount of capital gain in my IT return ? I don’t want the capital gain to affect any of their old age benefits like GIS.
Any solution for that?