One time alimony in mutually consented divorce.

My daughter married a gut about 4years and 8 months back. Both were living in a rented accommodation although the boy has a three story house in a posh colony but his mother did not allow them to stay there due to some family dues.The boy is the only son and there have huge immoveable property in Delhi including a hotel where in the boy is also a joint owner. The boy deserted my daughter about 8 months back saying he wanted to look after his parents. Since then my daughter has tried many a times to talk with the boy but he snubs her rudely each time she calls. Now we have met the parents of the boy and they want divorce. My question is, what amount of alimony would be just considering that we spent about 22 lac in the marriage and besides this she spent about 4 lac extra from her saving prior to marriage. My daughter was working and earning about 8 lac p.a which was spent there itself. The boy was only occasionally working and partly unemployed. In a way my daughter provided for the expenses. Can you suggest me a fair amount of alimony to be demanded from the boy or his parents. The boy is not working at the moment but owns a good amount of immoveable property running into crores and is the only son to his parents.