In-Laws in the Chart: the 8th as 2nd from the 7th

Start at the 7th, the spouse. The 2nd from there is family and speech of that spouse, and 2nd from the 7th is the 8th. A benefic 8th lord, or Jupiter aspecting the 8th, describes a smoother passage into that household. Saturn on the 8th describes delay, duty, or coldness in that passage. Rahu on the 8th describes an unusual or restless tie to the spouse's people. None of this is a character reference for a named mother-in-law. It is your chart's picture of the spouse's family as a house. Their actual natures are their own lagnas, which you do not get to invent.

If the friction is your parents refusing the match, that is your 2nd and 4th, not the 8th. The 2nd is your family and its speech. The 4th is the home. A 2nd lord in the 6th describes argument inside your own family. Treating that as an in-law problem sends the remedy to the wrong bhava. Venus remains the karaka of the marriage that has to stand between the two families. A strong Venus can hold a bond while the 8th is awkward. A weak Venus will not be saved by a Friday rite aimed vaguely at 'relatives.'

There is no graha whose job is to make someone like you. If you attend to a graha, attend to the 8th lord or to Venus after you know their houses, and do not feed a dusthana lord just because the wedding is soon. The dasha of the 7th lord is when the marriage, including its family, is loud. The dasha of the 8th lord is when the in-law house itself is loud. Showing up with ordinary respect is not an upay. It is also not something the chart can schedule. Read the 8th. Let the people be people.