Share in joint property is determined in the proportion of contribution made towards consideration by each.  Since your sister has not contributed anything towards consideration of the property she will not be eligible for any share in that property if a claim is made to this effect. 

Your sister will be eligible for alimony provided she is not capable of maintaining herself. No alimony can be claimed for adult children. Alimony and Monthly maintenance both can be claimed. 

Being joint owner surely creates right over the proper .

During decree of divorce, one time alimony can be claimed. 

Custody of children would be decided by the court..

Percentage is normally one third of total salary reviseable with the hike in salary with proper application. 

Wife only has right to stay in her matrimonial home 

2) since she has not contributed any funds for purchase of property property husband can file declaratory suit that he is absolute Owner of property 

3) wife can claim alimony from husband and maintenance for children 

4)it depends upon husband income, standard of living etc 

If she has not paid any consideration amount for the property, her husband can file a declaration suit and coat and can get her name removed as a co owner of the propertyvery he would have to prove that all the payments were made by him.

She cannot claim maintenance amount for a male child who is over 18 years old but for a a unmarried female she can claim maintenance amount from her husband.

Also, she only has a right to ask for monthly maintenance for herself which is decided on various factors by the court and is ideally 25% of the income of the husband. One time alimony is not awarded by the court, rather it is arrived upon by the parties.

Dear Client,

On the basis of ownership, your sister may claim 50% share in the property which in her name except alimony.

Being a co owner she will have a right if any percentage is decsied in sale deed. Alimony can be as per the various aspects and decision of court depending on her income, husbands income,  her standard of living etc.  If the flat doesn't have any money invested by her then your brother can file suit for cancellation of her being co-owner before civil court

See as of now she is equal owner of the property in case the husband file for declaration suit in that case she has to contest it. 

See she can quote an amount for one time settlement for herself or monthly maintenance court can award around 20 percent his salary to her, also for the children they can file for maintenance if they are above age of 18. 

In documents, she is co owner but not actually contributed in purchase so husband can get declaration from court of full ownership. Without court order, she owns half ownership.

And in any case she is entitle to alimony. She can 25% of net salary full life or till she remarries. Child expanses extra.

After the divorce, there are certain conditions under which the property is divided. If it is joint property, then the property is divided proportionally depending on the circumstances.You sister can claim permanent alimony. 

Dear client 

As both of them are co owner it's not a matter who is paying for the property and who is not she will get the share which is written in the registry papers. 

And maintenance is generally on the monthly basis.

For children father bound to pay maintenance for girl child till she is married and for son till he start earning for himself. 

If your sister is not employed and do not have any income to sustain her expenses then she may get at least 25% of his take home salary as monthly maintenance amount.

If her children are daughters then they will also get maintenance till the time they are getting married and that can be total 35 to 45%.

Besides, since she is a joint owner of the flats along with her husband, she is entitled to 50% share in each flat, he cannot deny that as per law.