issue

I've yet to find a birthday card with a "nice verse" EllanVannin, most of them are nauseating.

I'm inclined to agree with Gonegirl.

It shouldn't mean that her usual birthday card is 'cancelled' but your message will be a little different, that's all.

I think send a birthday card and just add, "thinking of you today Jane", with an extra kiss.

Always think of the living. A Birthday card with a nice verse.

I think I'd send a birthday card with a separate little note inside mentioning your brother. That way the card can be displayed and the note can be kept somewhere else.

for you travels

Nice plain card but say something like "Thinking of you on your birthday" and flowers as suggested by Namsnanny.

I think you should send your sister in law a birthday card. You cannot ignore her birthday forever because it is the anniversary of your brothers death. She deserves her birthday to be recognised.

I’d go with flowers and a pretty card with no words. Then you can add your own.

As jusnoneed said I think. Or a bunch of flowers delivered with a note saying ‘thought you might like these’

What a sad thing to happen on her birthday.
I'd send just a plain card with no sentiment, then write your own message inside.