1) summons have to be sent to address where H is presently residing

2) if W is not aware about H current address W should serve summons at last known address of H

3) apply to court for substitutes service

4)H can submit his reply duly attested before indian consulate through his lawyer

5) personal presence of H would be needed during trial

6) W need not appear in court on each date if she is represented by her lawyer

7) H can deny allegations in his reply and mention that wife has deserted husband on her own accord .not necessary to file separate petition for divorce

Without going to each of your questions, in nutshell a few points:

1) Summons are considered served as soon as these are delivered

2) You will be needed to attend the hearing in the court when the date appears. The jurisdiction will be where the marriage took place or the woman lives or where she filed the suit for divorce/maintenance.

3) Counter allegation would lead only to divorce as it will be proving the fact that the marriage is beyond repair and divorce is necessary.

When does the court consider the summons as "served"?

according to order 5 rule 15 of the code of civil procedure, [Where in any suit the defendant is absent from his residence at the time when the service of summons is sought to be effected on him at his residence.........................................service may be made on any adult member of the family, whether male or female, who is residing with him. ]

when your father accepted summon then court may declare that summon has properly served.

Can H submit response in writing or via a lawyer?

yes, you can file written statement either by a recognised agent or by your lawyer if he is acquainted with the facts and circumstances of the case. it is not mandatory that reply of plaint shall be submitted by the defendant.

Does W also need to appear in court on the date on which H is supposed to appear in court? If W needs to appear too, is that true for every single hearing?

your appearance is necessary when trial begins, but for the purpose of examination and submission of final argument. till then personal appearance not necessary.

What is the stance court is likely to take in this situation? When would the court consider the summons as "served"? What happens if the summons are not served, for whatever reason?

If she expresses before court that your address in India was the last known address, she may seek permission of court to take steps to serve summons by substituted service of summons i.e., by publishing the same through newspaper, then that will be deemed as proper service of summons.

2. Let's say the summons get served. Can H submit response in writing or via a lawyer? Or is H required to appear in person in front of the court on the date indicated on the summons?

On receipt of summons the H has to appear before court either in person or through his lawyer.

However in family courts' the presence of both parties to dispute is mandatory or they can be represented through their power agents too.

3. Does W also need to appear in court on the date on which H is supposed to appear in court? If W needs to appear too, is that true for every single hearing?

Both the parties are to appear before court, see the above anser for further details.

4. If H decides to respond making the counter-accusation that W's behavior was cruel and constructive desertion, would H need to file a separate petition, or could this be included in H's response to W's petition? If H needs to file a separate petition, would H need to appear in court physically, or can this be done via a lawyer?

The H has to appear before court whether he files counter or not, even if he engages an advocate.

H can file his counter to her allegations denying them in the same case itself.

It is a court case and not a pass time game you would to play.

H cannot appear in advance for the case to be heard on a later date.

He can file his response also on that date or any other future date of hearing.

H should file his written statement on date of the first hearing

2)court would not take your reply on record before the returnable date