mum massaging his back?

I don’t know if this is a me problem, it definitely could just be because I don’t have this type of relationship with my parents.

We’re both 24, we’re currently holidaying at her house due to her living in a different country& as we were all chatting she started putting sunscreen on his back&massaging it quite thoroughly and it’s just made me feel a bit icky?

We’re not married or engaged, only been together 4/5 years but she can be quite overbearing- understandably I suppose since he’s an only child. She can also be quite judgemental of myself as I’ve got quite a few tattoos&piercings& as autism/adhd runs in my family she’s ’joked’ that he should bring another girl next time and not to have children with me which can be quite hurtful, I haven’t even mentioned that I’ve been referred for an autism assessment myself bc I know her reaction wouldn’t be lovely. I’m just looking for a second opinion really, I’ll probably delete this after not too long.