@Astroboy2024 ,
Having read through this thread and generally agreeing with my colleague @Opus 17 , I have a slight different take on this situation.
You are correct that you don't have to issue a W-2 to your household " employee" but then you have to file Schedule-H.
The main difference of whom is an employee ( W-2 or Schedule-H ) and whom is a subcontractor ( 1099-NESC ) is really the control the employer exerts of how the work is done -- see below note from the IRS.
Hiring Household Employees | Internal Revenue Service (irs.gov)
Also please read the following ( at least peruse through so you are aware :(
p926.pdf (irs.gov)
As far a FICA / SECA area, there is really no age related exemption -- if you earn, you pay into Social Security and Medicare. So I don't see the difference between the two schemes you are proposing ( I recognize that this is not an area that I generally comment on because of lack of expertise and because there are others whom are more attuned to this topic ). Suggest you look into thew possibility of employing both and thus ensure that each can stand on his /her own feet ( even though they will file MFJ for the foreseeable future , but ultimately one will have to avail of Medicare by oneself
I don't know if this makes sense to you
pk
