I need advise on buying a house?PLEASE HELP!?

My husband parents gave him a old house paid off, lien free. So, I was wondering cause contactors have told me that they would have to strip the house but, it wasnt worth it and its better to remove this old house and build a house. I mean its livable beside the cracks and holes here and there. But I don't want to be dealing with holes and plumbing and electrical. I have asked around to my family. They all tell me its up to me I know it is but, I would really want someone advise. My husband loves the idea having our own house and not paying a mortgage he says leave this house here rent it and we buy a brand new house and we ever need to come back we could always come back mortgage free. I think of it like this could be our starter home build a new house on this property in 5-7 yr rent it for much more and buy a bigger house. I live in south texas in harlingen, texas. I would love some advise from realty, mortgage brokers and contractors or anyone with good advise. Send me advise because a mortgage is a big committment but , I really like knowing we are mortgage free here. But I dont want to look back and think man I should of done that instead with regret. THANKS.