Is it legal to manage money for other people (e.g. family members) in investments?

I believe legally you need to have a license to be mangaing other people's investment, especially if you are charging for your service.

However, if you are just doing in a very small scale with your close loved ones foc, I doubt you will really get into trouble.

For pooling money for investments, unless you are using a shared account to fund for investment I wont recommend it - always sensitive when you suddenly get a windfall or experience a huge loss.