All the dead limbs should be trimmed out and removed. If you are redoing an old or designing a new landscaping plan to build-in fire safety. Start with the idea that all or almost all within the first 30' should be fire proof. To make a landscaping cheaper, more fire resistant, and more attractive it is desirable to put walkways throughout this area of the plantings. The plantings then can be decreased in size to areas of 300-1000' sq.
Less water is needed, and less maintenance, while the result is firebreaks throughout the planting.
Most people are very happy with this because it gives access to the landscaping and makes a low maintenance landscaping even easier. Thin the brush and trees so that there is a 10'space between all plants 5' and over. The smaller plants can be left in clumps of 10' or less with 10-15' spaces between clumps. This gives a naturalized look to the landscape while it removes much of the potential fuel and makes what is there difficult to spread its flames. Do not forget to prune up and clean up the weeds.