The Moneyist: How do I give my sons investment tips — without being an interfering parent? ‘Advice can be ignored until hard lessons are learned.’

Dear Moneyist, 

My two sons are in their 30s and both well-educated with rewarding work. They save well and spend within their means, for which I’m very grateful. They both want to buy a home, for which saving is an almost Sisyphean effort as one lives in Boston and the other in San Francisco.   Both of which are great for real-estate investment, but terrible for first-time home buyers. They invest in equities, and they are excited about some of their hi-flyers.  

I…