Assalaamu alaykum. Please calculate the inheritance according to the following information:
- Does the deceased have male relatives who are entitled to inherit: (A son) Number 1
- Does the deceased have female relatives who are entitled to inherit: (A daughter) Number 3 (A wife) Number 1
- Information about the deceased’s debts: (Debts to people)
- Additional information: 20% money spent on marriages on 3 daughters by son, we have one small home of father, a lot of money was spent on medicaln expenses before death due to which the debt came into being.

All perfect praise be to Allaah, The Lord of the worlds. I testify that there is none worthy of worship except Allaah and that Muhammad, sallallaahu ‘alayhi wa sallam, is His slave and Messenger. 

If the deceased left no other heirs aside from those mentioned in the question, then the estate should be divided as follows:

The wife gets one eighth of the estate as a fixed share because the deceased has children. Allaah says (what means): {...But if you leave a child, then for them (i.e. the wives) is an eighth of what you leave, after any bequest you (may have) made or debt...} [Quran 4:12]

The remainder of the estate should be divided among the deceased's son and daughters by virtue of Ta‘seeb (by virtue of having a paternal relation with the deceased and not having an allotted share; they get what is left after the allotted shares are distributed); the male gets double the share of the female as Allaah, The Exalted, says (what means): {Allaah instructs you concerning your children (i.e. their portions of inheritance): for the male, what is equal to the share of two females...}[Quran 4:11]

Hence, the estate should be divided into forty shares; the wife gets one-eighth (five shares), the son gets fourteen shares, and each daughter gets seven shares.

As for the debts, if they have been incurred to pay for the treatment expenses of the father, then they must be deducted from the estate first before it is divided among the heirs. Allaah says (what means): {...after any bequest you (may have) made or debt...} [Quran 4:11]

As for bearing part of the marriage expenses of the daughters' marriages by their brother (the deceased's son), scholars held different views as to whether the husband or the wife is the one who is legislatively obliged to furnish the marital house. Since scholars held different opinions in this regard, this matter cannot be decided except by referring it to a Sharee'ah court to investigate the matter thoroughly and issue its verdict.

As for the house owned by the deceased, it should be added to his other properties to be distributed among the eligible heirs according to the Sharee'ah inheritance laws.

Finally, it should be noted that the division of inheritance is a very serious and complex issue. Therefore, the inheritance should not be divided without resorting to an Islamic court, if available, in order to fulfill the interests of both the living and the dead.

Allaah knows best.