Is a married man who lives far from his parents and allocates a monthly salary for them obligated to buy home appliances for his parents, just as he buys for his own family, given that he cannot afford to buy for both?

You are not obligated to buy for your parents what you buy for your own household. However, if they are poor, you must spend on them reasonably if you are well-off. Scholars unanimously agree on the obligation to financially support poor parents who have no wealth or income. If they are not in need, spending on them is not obligatory but rather an act of kindness and a righteous deed. Showing kindness to parents and prioritizing them holds great merit and immense reward.