Nah, I don't see this as a negative slight at all. I don't see where this could be abusive and I certainly don't view this as being selfish or picking on you. What I do see is merely a communication issue. Your father in my opinion simply failed to choose kinder gentler words to suggest the problem with your visits is that they put pressure on your mother on account of her limited mobility. What I see happening is that your mom wishes to be a good hostess. It may be that visits put physical stress on her as a result of over-doing it.

The solution maybe as simple as giving her the freedom not to put herself out. This could be an offer of bringing something by or contributing to things like errands around the house. I think it more about mom being comfortable than anything else. Your dad just didn't find the words to better express this.

Of course, you could always ask him, "What can I do then?"