I agree, presenting bitcoin as an investment is not a good way of promoting it. If you help relative or friends to buy bitcoins as an investment, you should expect to get shit when its value lowers. Bitcoin should be presented as a secure way of exchanging and storing value. The value it could have in 1, 5 or 10 years should not be relevant.
Yeah that could work if bitcoin to be cnsider as an investment holding it for long term would be better. Just let them decide what they think is better after explaining to them cons and pros. It is simple I guess just to let them decide for themselves and do not interfere so as to avoid any possible regrets from them.
However, I do not see bitcoin a good neither bad investment because I do believe that investment matters on your attitude. How your manners towards a certain investment really matters and that is basing on how I see others that are successful in their investment no matter how small or big or hard it may be as long as one endure and be patient for success to achieve.