Texas is a community property state and it depends on what relatives you are talking about.
§ 45. COMMUNITY ESTATE. (a) On the intestate death of one
of the spouses to a marriage, the community property estate of the
deceased spouse passes to the surviving spouse if:
(1) no child or other descendant of the deceased spouse
survives the deceased spouse; or
(2) all surviving children and descendants of the deceased
spouse are also children or descendants of the surviving spouse.
(b) On the intestate death of one of the spouses to a
marriage, if a child or other descendant of the deceased spouse
survives the deceased spouse and the child or descendant is not a
child or descendant of the surviving spouse, one-half of the
community estate is retained by the surviving spouse and the other
one-half passes to the children or descendants of the deceased
spouse. The descendants shall inherit only such portion of said
property to which they would be entitled under Section 43 of this
code. In every case, the community estate passes charged with the
debts against it.
If they are her children only, they do they have a claim but only to one half of her portion of the community property. Her children would get one fouth in other words. As for the house it depends on how it is titled. If it is joint with right of survivorship it is all his. He may need to open probate.