it would depend upon reliefs claimed in appeal 

2) if husband is not contesting divorce but only alimony amount awarded divorce decree would not be set aside 

Only if high court stays the order of trial court then it will affect alimony otherwise no

Hi

When he is intending to file case against alimony, the question of affecting divorce does not  arise.

No divorce granted may not be cancelled.

Going by your post, he is going  to challenge the quantum of alimony.

Need not worry.

File CAVEAT in the High Court.

Good Luck

No, if he is contesting limited portion of order i.e. alimony, no effect on divorce.

 divorce decree is final which is allowed by the family court so the marriage is now dissolved so far as the alimony is concerned he can file revision petition in High Court and until and unless he do not pay them amount decided by the court you can take objection in case he moves for marriage  without payment of alimony this is the condition of the diverse and the diverse will be complete only after the payment of alimony amount as decided by the court on revision petition High Court do not take lot of time in case you have anything to submit to contest the alimony you can do so

He can appeal the order of divorce and amount both before the high court. The divorce may or may not be cancelled but if he file timely appeal and has substantive grounds there can be a stay on order below. 

Once the divorce is completed and a judgment entered, either or both spouses can appeal a trial court judge's decision to a higher ("appellate" or "appeals") court. 

No it will not affect the judgement of Divorce as her husband is challenging only alimony amount in high court.