Ruling on doing the obligatory Hajj on behalf of someone who has lost his memory

He has a piece of land which he is keeping in case he needs it; does he have to sell it in order to do Hajj?

Can he take money from his son to do Hajj?

She was financially and physically able but she did not do Hajj because she had no mahram, then she died. Is it obligatory to do Hajj on her behalf?

Should he gave precedence to Hajj over taking a second wife?

She does not have any wealth; can she take money from her father in order to do Hajj? Can she delegate someone to perform Hajj on her behalf if she is not able to do Hajj?

Should he give up his place in the Hajj lottery to his father even though he has not yet done the obligatory Hajj?

Is the Hajj of one who has not paid off his debts valid?

Is a woman obliged to sell her jewellery so that she can do the obligatory Hajj?

Should he perform the obligatory Hajj or give the money in charity to his neighbour who is poor?