Housing one’s parent in one’s own home:

Seemingly, included in the command of honoring one’s parents through entering and leaving, is to house one’s parents in his own home, if he does not wish to rent them a home, or if they cannot afford it. The same applies if the parent is old and is unable to care for himself and requests to live in the same home as their child.[1] [Nonetheless, the expenses involved in housing the parent does not have to be from the possessions of the child, and he may request monetary compensation from his parents for housing them. This especially applies if the room or home is available for rent, that the son may request the parent to pay him the rent.] One who opens their home for their parent to living ends up fulfilling the mitzvah of Kibbud Av Vaeim at every moment. [Another option to housing the parent within one’s house if doing so is most difficult or has spousal opposition, is to rent a nearby home on behalf of the parent.]

If one spouse opposes the idea:[2] If one’s spouse is opposed to having their father or mother in-law live with them at home due to justified reasons relating to Shalom Bayis, then they are not required to house the parent in their home. This applies whether the wife opposes it, or the husband opposes, and certainly if both agree that it is not a good idea due to the friction that it may create. In such a case, the child was obligated to find a replacement option for housing the parent.

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[1] Rav Elyashiv in Avnei Zikaron p. 281; Teshuvos Vehanhagos 2:444; Vayivarech Dovid 35; Derech Sicha p. 288; Mayim Amukim 2:101

[2] See Michaber and Rama E.H. 74:10; Rambam Ishus 13:14; Mishkanos Haroim Mareches Daled 20; Devar Moshe 1; Yaskil Avdi E.H. 5:58; Shevet Halevi 9:197