If you are elderly or disabled, there might be social service agencies that can assist with the work or financials....dial 211 if the phone co in your neighborhood uses that system for getting referral assistance.
It's hard to picture the situation, but a can of premixed latex stucco repair (unsanded) might do the trick temporarily....I used it to repair stucco on concrete block and even to "mortar" in some cement bricks to fill a void in ccb. It is paintable, cheap and easy to use. Thick applications shrink a tad and might require a second app; be sure the area is dry first, then caulk around that and paint it. It certainly isn't a great repair, but probably better at keeping out the elements than spray foam.
If those aren't do-able, call a siding company or handyman for an estimate; there are good-hearted folks who might just do the job gratis; BTDT.