Maintenance amount to wife and kid

Recently one of my women relative got divorced, I would like to know how much maintenance amount she can claim. Family Situation: 1. Husband - Doctor - Around 1 lakh salary (I am sure he must be filing income tax). Another 1 lakh from practices which might not be documented. Total - 2 lakh. 2. Wife - Teacher - earns around 28 K 3. Son - 16 year. Additional cost due to medical/engineering coaching, plus cost of stating in hostel 4. Daughter - who is is not physically fit 5. 10 Yr old daughter 6. 5 Yr old daughter. Q1: How total household income will be calculated? (Wife's income + Husband taxable income+ Husband undocumented income)? Q2: What percentage of total household income will be allocated to wife as a monthly maintenance if kid stays with her. Q3: Does extra amount will be allocated for education of child. e.g Hostel expense, Coaching expense, school expense, purchasing electronic equipment, internet expense etc.. Q3: Where can I file the case for maintenance claim , please share section number?