Madam Apoorva
In the chart of your younger sister, 7th cusp (marriage) sub lord Moon is in the star of Ketu in 9th house (bhagya or purva punya sthana). Ketu as a node signifies it sign lord Jupiter in 2nd house (addition to family) and 7th lord Venus and Sun. Venus signifies Mercury in 11th house. So she is destined to marriage.
As Mercury is the lord of 6th house (separation by husband, her service in job), but 6th cusp sub lord Jupiter is signifying 9th through his star lord Moon and 11th house through his sub lord Mars.
As Venus is in 12th house (separation by the native), 12th cusp sub lord Rahu is signifying Jupiter in 2nd house (addition to family). As a node Rahu is signifying Mercury in 11th house (fulfilment of desires). So there would be no separation to them.
Dasa nadha Sun is signifying Jupiter in 2nd house and through his sub lord Rahu signifying 11th house and 6th house. So Sun gives her marriage with some disturbances because of 6th house.
Mars bhukti is favourable for her. Mars bhukti is from 3-1-2026 to 11-5-2026. In this period the marriage would be over. Even you do parihara or not, the marriage would be over. It is your look out.
God bless you all.
Good Luck
JVS Rao (KP system follower)