Aside bitcoin investment it is very wrong to force people to invest in any investment they don't want to since you won't bear the loss with them if any because bitcoin investment is risky due to the volatile nature of bitcoin. however you can only advise them or guide them on the nature of the investment are introducing then. So it is left for them to decide whether to invest or not. I believe bitcoin has reached a stage where by people don't need to be forced to invest in it, rather they will be moved by what they have seen because people are mostly moved by result rather than action.
Sometimes I used to wonder why someone would have such thought, noing fully well that Bitcoin is not a get rich quick scheme. However, is totally wrong to force someone into something that is not in their budget, even though it look somehow to me because if anything happens along the line you be held responsible for their losses.
It's very essential for us to always understand that Bitcoin investment is only profitable when you invest for future purposes, that is the main reason why is not advisable to force someone because is something that required time and patience.