I don't know what has happened to my holly trees. I have a number of them and they are all beginning to look like this. Help
Welcome to the forum
Do you know how long they've been in the garden ? The leaf shape looks like euonymus to me, l'm not sure they are holly ?
If possible, can you post a more close up of the leaves? Perhaps another one with the base of the plant. I do think it is Holly, and a congested looking one that is crowded with nearby shrubs or possibly looking like some reversion on some branches.
On some of the photos, it shows some recent pruning happening, and new growth seems to be happening.
The dry and warm weather may not have helped. I think it may need some pruning back to rejuvenate the shrub, and possible watering and then new mulch thrown down after the base has been cleared.