Observations first:
1. In first query you mentioned friend's mom working somewhere else. In second query you are mentioning she is staying in same house.
2. In first query you mentioned friend's dad received property via partition and in second query you are asking about injunction of the very properties.
Above being material from the briefs, now I am attempting my opinion on your second query;
Now your que. # 1: "Can my major friend file a suit for injunction not to sell the house or vacant land?"
Take: If the property of the grand father was his self acquired property then this property shall devolve to all his legal heir if he died intestate i.e. no testamentary document such as 'will' exist with regard to the property made by him during his life time. The grandson is not legal heir if his father is alive in such case, in case the father of the grandson died before the death of grand father then the grandson being son of the predeceased son get the share in the property which his father would have got, sharing that share along with his mother i.e. widow of his father. Hence in present facts situation your friend has no legal claim on mentioned properties since his father is alive and moreover the said properties are already partitioned off. My guess is by now your friend's father might have also initiated 'disowning' via paper publication of your friend who is now major. Here disowning means your friend has no legal right son properties including F/D of his father ! Your friend will discover this aspect the moment he approaches Court believe me as I see this query evolving thus prompted me to comment in such a way J
Further to your que. # 2: "Can my friend's mom file a suit for maintenance or alimony now?"
Take: Your friend's ex parted divorced mom is first required to set aside the ex parte divorce in jurisdiction Court whose brief details I suggested earlier on how to go about and yes even after 4 years the said ex parte decree can be set aside as the knowledge of it she and your major friend came to know just yesterday as you say in yoru above brief(s) and unless your friend and his mother act very fast via appointing locally an advocate via reference we will end up here just talking and talking. However to your question on alimony (full and final permanent maintenance to a divorced wife) if she is working lady then she is not entitled for alimony is my view. To your previous question on maintenance (interim maintenance while case on floor of a Court) once she attempts (succeeds) setting aside ex parte decree in divorce she can just 'file' for interim maintenance though being working lady but I still reserve my doubt that she will be able to get any interim maintenance during re-opened up ex parte divorce proceedings. However worth trying.
On your inference on F/D of 36 L etc. your major friend and his working mother has no claims over it till ex husband / natural father is alive. Yes, the minor child maintenance till he also becomes major as claim are always there but for the same your friends dad wants to keep the minor child with him which is what you say to us so the moment he says so in yet to open ex parte divorce case the reference Court will not grant maintenance for the minor brother of your friend as he is in safety, security and in welfare of his natural father's company is also my hi-tea view. However there may be few sips between cup and lips so until reference brief's mentioned case is re-opened up all finality as legal reply cannot forthcoming in one shot ! Please understand some limitations are there in internet queries where we have no access of actual court proceedings papers / decree sheet / final judgement etc. and related property papers are also not shown to us but just some queries by a third party are presented here and to these I can only give actual position and now it depends on your friend and his mom to do Chamber discussion with a reference advocate and set the wheel of law in motion.
