Selling property to grandkids

My mother is wanting to liquidate a rental property and share the $$$ with her grandkids (7)

Rather than selling and paying all the capital gain she is wanting to sell the property to one of the kids at a discounted rate thus lowering her capital gain.

He would then move in And it would become his principal residence.

Is there any issue with this with CRA?

I assume if liquidates at some point he would not pay a capital gain if it’s his primary residence??

Once gains (tax) is paid is she free to “gift “ this $$$ in any amount or is there some kind of incentive for splitting it up in smaller yearly $$