It's not late to try, but you may not succeed--even if the concrete was broken, it is natural that a boat ramp would be slippery, and slipping on wet concrete on such a ramp is a natural and normal risk of using such a ramp. That means that in using it, your husband "assumed the risk" of slipping and injuring himself. Normally, assuming a risk precludes suing or taking legal action for the normal injuries associated with that risk. Now, because there was, as you write, also evidentally broken concrete, which would represent negligent maintenance, it may be that that assumption of the risk does not bar recovering compensation, but it is possible that this assumption might preclude compensation--or at least reduce it in proportion to the normal risk which your husband would be deemed to have assumed (as opposed to non-normal risk flowing out of broken concrete).To seek compensation, contact the person or entity which is resonsible for maintaining the boat ramp. If you don't know whether it was the homeowner or the HOA, contact both. If no one (or their insurers) offers to voluntarily pay compensation (such as the medical bills), you could next try suing--but bear in mind that, as per the above, it's not a given that you would succeed.