Is it obligatory to give a relative a share of the profits resulting from the sale of shares, knowing that a portion of these shares was purchased with his money, and that he recovered his money before these profits were realized and waived them?

If you offer to your relative to buy shares within your portfolio, on the condition that you split the profits equally, then this is a Mudarabah (profit-sharing partnership). Its conditions are that the profit must be a specified percentage and the capital is not guaranteed. If the contract is concluded on this basis, the Mudarabah is valid, and each of you has his right to the profit. Neither of the contracting parties has the right to compel the other to sell the goods before their market time. However, if one party waives his share of the profit and requests his share of the capital, and the partner gives it to him voluntarily, there is no harm in that.