The best thing to do is put the son on the account as beneficiary. When the father passes, this has a full step up in basis to the son. Why put the son in a position of having potentially large tax bills, assuming the father has had these holdings for a while? Why not make it nearly tax free?

If the son needs money, the father can use the gift rules, and sell some stock to fund the gift.

Right now, this initial idea is one of the worst.